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Schlagwort: Vulnerability Report

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17. Februar 2025 / / Ein Kommentar
Vulnerability Report

Vor Kurzem habe ich einen Vulnerability Report erhalten. Ich freue mich natürlich immer über solche Hinweise – sie helfen mir, zu wachsen und mein Setup zu verbessern, bevor jemand eine Schwachstelle tatsächlich ausnutzt.

Der Report lautet wie folgt:

Subject: Vulnerability Report: Vulnerable System Detected at openpgpkey.kernel-error.com

Hello Team,

I have identified a security issue in your system related to a vulnerability (CVE-2023-48795) in Terrapin.

Vulnerability Details:
- CVE Identifier: CVE-2023-48795
- Vulnerability Type: javascript
- Severity: medium
- Host: openpgpkey.kernel-error.com
- Affected Port: 22

Description: A security vulnerability (CVE-2023-48795) related to Terrapin has been detected in your system. This vulnerability could be exploited to compromise your system's security. Please see the details below for more information.

Impact: Impact:
1. Potential for Unauthorized Access: Attackers may exploit this vulnerability to gain unauthorized access.
2. System Compromise: Vulnerable systems could be compromised, leading to data loss or further attacks.
3. Increased Attack Surface: Exposing systems with this vulnerability increases the risk of exploitation.


Recommendation: Recommendation:
1. Apply patches for CVE-2023-48795: Ensure your systems are updated to address this vulnerability.
2. Conduct a Security Review: Regularly review and update your security policies and procedures.
3. Monitor for Suspicious Activity: Implement continuous monitoring to detect any potential exploitation attempts.
4. Restrict Access: Limit access to systems vulnerable to exploitation.


Best Regards,
Security Team

Ich war mir eigentlich sicher, dass ich Terrapin schon vor langer Zeit überall gepatcht und in den SSH-Konfigurationen berücksichtigt hatte.

Dann kam der Hinweis auf openpgpkey.kernel-error.com. Die Domain existiert als CNAME und gehört zur Web Key Directory (WKD), was im Groben dazu dient, öffentliche GPG-Keys möglichst automatisiert abrufen zu können. Wenn mir also jemand eine Mail schreiben möchte, aber meinen öffentlichen Key nicht hat, kann er diesen einfach über WKD beziehen. Ich habe das Ganze als CNAME zu wkd.keys.openpgp.org angelegt, weil dieser Keyserver zumindest eine E-Mail-Validierung beim Hochladen öffentlicher Schlüssel durchführt. Ich muss ja nicht jede Infrastruktur selbst betreiben.

Allerdings gehört der betroffene SSH-Server und das gesamte Zielsystem somit gar nicht zu meiner Infrastruktur – ich kann also selbst nichts tun.

Vulnerability Type: JavaScript

Das verstehe ich nicht ganz. Vermutlich hat der Finder einfach sein Standard-Template benutzt und nicht angepasst?! Aber zumindest wollte ich prüfen, ob seine Einschätzung zum SSH-Server überhaupt zutrifft:

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# general
(gen) banner: SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3
(gen) software: OpenSSH 8.4p1
(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+
(gen) compression: enabled (zlib@openssh.com)
# security
(cve) CVE-2021-41617 -- (CVSSv2: 7.0) privilege escalation via supplemental groups
(cve) CVE-2016-20012 -- (CVSSv2: 5.3) enumerate usernames via challenge response
# key exchange algorithms
(kex) curve25519-sha256 -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
`- [info] default key exchange since OpenSSH 6.4
(kex) curve25519-sha256@libssh.org -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
`- [info] default key exchange since OpenSSH 6.4
(kex) ecdh-sha2-nistp256 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
`- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp384 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
`- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp521 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
`- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) diffie-hellman-group-exchange-sha256 (3072-bit) -- [info] available since OpenSSH 4.4
`- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 3072. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477).
(kex) diffie-hellman-group16-sha512 -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) diffie-hellman-group18-sha512 -- [info] available since OpenSSH 7.3
(kex) diffie-hellman-group14-sha256 -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
`- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) kex-strict-s-v00@openssh.com -- [info] pseudo-algorithm that denotes the peer supports a stricter key exchange method as a counter-measure to the Terrapin attack (CVE-2023-48795)
# host-key algorithms
(key) rsa-sha2-512 (2048-bit) -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
`- [info] available since OpenSSH 7.2
(key) rsa-sha2-256 (2048-bit) -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
`- [info] available since OpenSSH 7.2
(key) ssh-rsa (2048-bit) -- [fail] using broken SHA-1 hash algorithm
`- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
`- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
`- [info] deprecated in OpenSSH 8.8: https://www.openssh.com/txt/release-8.8
(key) ecdsa-sha2-nistp256 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
`- [warn] using weak random number generator could reveal the key
`- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(key) ssh-ed25519 -- [info] available since OpenSSH 6.5
# encryption algorithms (ciphers)
(enc) chacha20-poly1305@openssh.com -- [info] available since OpenSSH 6.5
`- [info] default cipher since OpenSSH 6.9
(enc) aes128-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) aes192-ctr -- [info] available since OpenSSH 3.7
(enc) aes256-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) aes128-gcm@openssh.com -- [info] available since OpenSSH 6.2
(enc) aes256-gcm@openssh.com -- [info] available since OpenSSH 6.2
# message authentication code algorithms
(mac) umac-64-etm@openssh.com -- [warn] using small 64-bit tag size
`- [info] available since OpenSSH 6.2
(mac) umac-128-etm@openssh.com -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-256-etm@openssh.com -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-512-etm@openssh.com -- [info] available since OpenSSH 6.2
(mac) hmac-sha1-etm@openssh.com -- [fail] using broken SHA-1 hash algorithm
`- [info] available since OpenSSH 6.2
(mac) umac-64@openssh.com -- [warn] using encrypt-and-MAC mode
`- [warn] using small 64-bit tag size
`- [info] available since OpenSSH 4.7
(mac) umac-128@openssh.com -- [warn] using encrypt-and-MAC mode
`- [info] available since OpenSSH 6.2
(mac) hmac-sha2-256 -- [warn] using encrypt-and-MAC mode
`- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56
(mac) hmac-sha2-512 -- [warn] using encrypt-and-MAC mode
`- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56
(mac) hmac-sha1 -- [fail] using broken SHA-1 hash algorithm
`- [warn] using encrypt-and-MAC mode
`- [info] available since OpenSSH 2.1.0, Dropbear SSH 0.28
# fingerprints
(fin) ssh-ed25519: SHA256:vwCCSg+OuRwAflHQs/+Y22UJ7p2lM57vbukGFt5AAaY
(fin) ssh-rsa: SHA256:o+WUM9bAmH2G5xMAsJfZRsmh8hvMoU4dx9gdmahLM+M
# algorithm recommendations (for OpenSSH 8.4)
(rec) -ecdh-sha2-nistp256 -- kex algorithm to remove
(rec) -ecdh-sha2-nistp384 -- kex algorithm to remove
(rec) -ecdh-sha2-nistp521 -- kex algorithm to remove
(rec) -ecdsa-sha2-nistp256 -- key algorithm to remove
(rec) -hmac-sha1 -- mac algorithm to remove
(rec) -hmac-sha1-etm@openssh.com -- mac algorithm to remove
(rec) -ssh-rsa -- key algorithm to remove
(rec) !rsa-sha2-256 -- key algorithm to change (increase modulus size to 3072 bits or larger)
(rec) !rsa-sha2-512 -- key algorithm to change (increase modulus size to 3072 bits or larger)
(rec) -diffie-hellman-group14-sha256 -- kex algorithm to remove
(rec) -hmac-sha2-256 -- mac algorithm to remove
(rec) -hmac-sha2-512 -- mac algorithm to remove
(rec) -umac-128@openssh.com -- mac algorithm to remove
(rec) -umac-64-etm@openssh.com -- mac algorithm to remove
(rec) -umac-64@openssh.com -- mac algorithm to remove
# additional info
(nfo) For hardening guides on common OSes, please see: <https://www.ssh-audit.com/hardening_guides.html>
(nfo) Be aware that, while this target properly supports the strict key exchange method (via the kex-strict-?-v00@openssh.com marker) needed to protect against the Terrapin vulnerability (CVE-2023-48795), all peers must also support this feature as well, otherwise the vulnerability will still be present. The following algorithms would allow an unpatched peer to create vulnerable SSH channels with this target: chacha20-poly1305@openssh.com. If any CBC ciphers are in this list, you may remove them while leaving the *-etm@openssh.com MACs in place; these MACs are fine while paired with non-CBC cipher types.
# general (gen) banner: SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3 (gen) software: OpenSSH 8.4p1 (gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+ (gen) compression: enabled (zlib@openssh.com) # security (cve) CVE-2021-41617 -- (CVSSv2: 7.0) privilege escalation via supplemental groups (cve) CVE-2016-20012 -- (CVSSv2: 5.3) enumerate usernames via challenge response # key exchange algorithms (kex) curve25519-sha256 -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76 `- [info] default key exchange since OpenSSH 6.4 (kex) curve25519-sha256@libssh.org -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62 `- [info] default key exchange since OpenSSH 6.4 (kex) ecdh-sha2-nistp256 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62 (kex) ecdh-sha2-nistp384 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62 (kex) ecdh-sha2-nistp521 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62 (kex) diffie-hellman-group-exchange-sha256 (3072-bit) -- [info] available since OpenSSH 4.4 `- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 3072. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477). (kex) diffie-hellman-group16-sha512 -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73 (kex) diffie-hellman-group18-sha512 -- [info] available since OpenSSH 7.3 (kex) diffie-hellman-group14-sha256 -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength `- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73 (kex) kex-strict-s-v00@openssh.com -- [info] pseudo-algorithm that denotes the peer supports a stricter key exchange method as a counter-measure to the Terrapin attack (CVE-2023-48795) # host-key algorithms (key) rsa-sha2-512 (2048-bit) -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength `- [info] available since OpenSSH 7.2 (key) rsa-sha2-256 (2048-bit) -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength `- [info] available since OpenSSH 7.2 (key) ssh-rsa (2048-bit) -- [fail] using broken SHA-1 hash algorithm `- [warn] 2048-bit modulus only provides 112-bits of symmetric strength `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28 `- [info] deprecated in OpenSSH 8.8: https://www.openssh.com/txt/release-8.8 (key) ecdsa-sha2-nistp256 -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency `- [warn] using weak random number generator could reveal the key `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62 (key) ssh-ed25519 -- [info] available since OpenSSH 6.5 # encryption algorithms (ciphers) (enc) chacha20-poly1305@openssh.com -- [info] available since OpenSSH 6.5 `- [info] default cipher since OpenSSH 6.9 (enc) aes128-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52 (enc) aes192-ctr -- [info] available since OpenSSH 3.7 (enc) aes256-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52 (enc) aes128-gcm@openssh.com -- [info] available since OpenSSH 6.2 (enc) aes256-gcm@openssh.com -- [info] available since OpenSSH 6.2 # message authentication code algorithms (mac) umac-64-etm@openssh.com -- [warn] using small 64-bit tag size `- [info] available since OpenSSH 6.2 (mac) umac-128-etm@openssh.com -- [info] available since OpenSSH 6.2 (mac) hmac-sha2-256-etm@openssh.com -- [info] available since OpenSSH 6.2 (mac) hmac-sha2-512-etm@openssh.com -- [info] available since OpenSSH 6.2 (mac) hmac-sha1-etm@openssh.com -- [fail] using broken SHA-1 hash algorithm `- [info] available since OpenSSH 6.2 (mac) umac-64@openssh.com -- [warn] using encrypt-and-MAC mode `- [warn] using small 64-bit tag size `- [info] available since OpenSSH 4.7 (mac) umac-128@openssh.com -- [warn] using encrypt-and-MAC mode `- [info] available since OpenSSH 6.2 (mac) hmac-sha2-256 -- [warn] using encrypt-and-MAC mode `- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56 (mac) hmac-sha2-512 -- [warn] using encrypt-and-MAC mode `- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56 (mac) hmac-sha1 -- [fail] using broken SHA-1 hash algorithm `- [warn] using encrypt-and-MAC mode `- [info] available since OpenSSH 2.1.0, Dropbear SSH 0.28 # fingerprints (fin) ssh-ed25519: SHA256:vwCCSg+OuRwAflHQs/+Y22UJ7p2lM57vbukGFt5AAaY (fin) ssh-rsa: SHA256:o+WUM9bAmH2G5xMAsJfZRsmh8hvMoU4dx9gdmahLM+M # algorithm recommendations (for OpenSSH 8.4) (rec) -ecdh-sha2-nistp256 -- kex algorithm to remove (rec) -ecdh-sha2-nistp384 -- kex algorithm to remove (rec) -ecdh-sha2-nistp521 -- kex algorithm to remove (rec) -ecdsa-sha2-nistp256 -- key algorithm to remove (rec) -hmac-sha1 -- mac algorithm to remove (rec) -hmac-sha1-etm@openssh.com -- mac algorithm to remove (rec) -ssh-rsa -- key algorithm to remove (rec) !rsa-sha2-256 -- key algorithm to change (increase modulus size to 3072 bits or larger) (rec) !rsa-sha2-512 -- key algorithm to change (increase modulus size to 3072 bits or larger) (rec) -diffie-hellman-group14-sha256 -- kex algorithm to remove (rec) -hmac-sha2-256 -- mac algorithm to remove (rec) -hmac-sha2-512 -- mac algorithm to remove (rec) -umac-128@openssh.com -- mac algorithm to remove (rec) -umac-64-etm@openssh.com -- mac algorithm to remove (rec) -umac-64@openssh.com -- mac algorithm to remove # additional info (nfo) For hardening guides on common OSes, please see: <https://www.ssh-audit.com/hardening_guides.html> (nfo) Be aware that, while this target properly supports the strict key exchange method (via the kex-strict-?-v00@openssh.com marker) needed to protect against the Terrapin vulnerability (CVE-2023-48795), all peers must also support this feature as well, otherwise the vulnerability will still be present. The following algorithms would allow an unpatched peer to create vulnerable SSH channels with this target: chacha20-poly1305@openssh.com. If any CBC ciphers are in this list, you may remove them while leaving the *-etm@openssh.com MACs in place; these MACs are fine while paired with non-CBC cipher types.
# general
(gen) banner: SSH-2.0-OpenSSH_8.4p1 Debian-5+deb11u3
(gen) software: OpenSSH 8.4p1
(gen) compatibility: OpenSSH 7.4+, Dropbear SSH 2018.76+
(gen) compression: enabled (zlib@openssh.com)

# security
(cve) CVE-2021-41617                        -- (CVSSv2: 7.0) privilege escalation via supplemental groups
(cve) CVE-2016-20012                        -- (CVSSv2: 5.3) enumerate usernames via challenge response

# key exchange algorithms
(kex) curve25519-sha256                     -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
                                            `- [info] default key exchange since OpenSSH 6.4
(kex) curve25519-sha256@libssh.org          -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
                                            `- [info] default key exchange since OpenSSH 6.4
(kex) ecdh-sha2-nistp256                    -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                            `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp384                    -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                            `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) ecdh-sha2-nistp521                    -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                            `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(kex) diffie-hellman-group-exchange-sha256 (3072-bit) -- [info] available since OpenSSH 4.4
                                                      `- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 3072. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477).
(kex) diffie-hellman-group16-sha512         -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) diffie-hellman-group18-sha512         -- [info] available since OpenSSH 7.3
(kex) diffie-hellman-group14-sha256         -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
                                            `- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) kex-strict-s-v00@openssh.com          -- [info] pseudo-algorithm that denotes the peer supports a stricter key exchange method as a counter-measure to the Terrapin attack (CVE-2023-48795)

# host-key algorithms
(key) rsa-sha2-512 (2048-bit)               -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
                                            `- [info] available since OpenSSH 7.2
(key) rsa-sha2-256 (2048-bit)               -- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
                                            `- [info] available since OpenSSH 7.2
(key) ssh-rsa (2048-bit)                    -- [fail] using broken SHA-1 hash algorithm
                                            `- [warn] 2048-bit modulus only provides 112-bits of symmetric strength
                                            `- [info] available since OpenSSH 2.5.0, Dropbear SSH 0.28
                                            `- [info] deprecated in OpenSSH 8.8: https://www.openssh.com/txt/release-8.8
(key) ecdsa-sha2-nistp256                   -- [fail] using elliptic curves that are suspected as being backdoored by the U.S. National Security Agency
                                            `- [warn] using weak random number generator could reveal the key
                                            `- [info] available since OpenSSH 5.7, Dropbear SSH 2013.62
(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5

# encryption algorithms (ciphers)
(enc) chacha20-poly1305@openssh.com         -- [info] available since OpenSSH 6.5
                                            `- [info] default cipher since OpenSSH 6.9
(enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) aes192-ctr                            -- [info] available since OpenSSH 3.7
(enc) aes256-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) aes128-gcm@openssh.com                -- [info] available since OpenSSH 6.2
(enc) aes256-gcm@openssh.com                -- [info] available since OpenSSH 6.2

# message authentication code algorithms
(mac) umac-64-etm@openssh.com               -- [warn] using small 64-bit tag size
                                            `- [info] available since OpenSSH 6.2
(mac) umac-128-etm@openssh.com              -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-256-etm@openssh.com         -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-512-etm@openssh.com         -- [info] available since OpenSSH 6.2
(mac) hmac-sha1-etm@openssh.com             -- [fail] using broken SHA-1 hash algorithm
                                            `- [info] available since OpenSSH 6.2
(mac) umac-64@openssh.com                   -- [warn] using encrypt-and-MAC mode
                                            `- [warn] using small 64-bit tag size
                                            `- [info] available since OpenSSH 4.7
(mac) umac-128@openssh.com                  -- [warn] using encrypt-and-MAC mode
                                            `- [info] available since OpenSSH 6.2
(mac) hmac-sha2-256                         -- [warn] using encrypt-and-MAC mode
                                            `- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56
(mac) hmac-sha2-512                         -- [warn] using encrypt-and-MAC mode
                                            `- [info] available since OpenSSH 5.9, Dropbear SSH 2013.56
(mac) hmac-sha1                             -- [fail] using broken SHA-1 hash algorithm
                                            `- [warn] using encrypt-and-MAC mode
                                            `- [info] available since OpenSSH 2.1.0, Dropbear SSH 0.28

# fingerprints
(fin) ssh-ed25519: SHA256:vwCCSg+OuRwAflHQs/+Y22UJ7p2lM57vbukGFt5AAaY
(fin) ssh-rsa: SHA256:o+WUM9bAmH2G5xMAsJfZRsmh8hvMoU4dx9gdmahLM+M

# algorithm recommendations (for OpenSSH 8.4)
(rec) -ecdh-sha2-nistp256                   -- kex algorithm to remove 
(rec) -ecdh-sha2-nistp384                   -- kex algorithm to remove 
(rec) -ecdh-sha2-nistp521                   -- kex algorithm to remove 
(rec) -ecdsa-sha2-nistp256                  -- key algorithm to remove 
(rec) -hmac-sha1                            -- mac algorithm to remove 
(rec) -hmac-sha1-etm@openssh.com            -- mac algorithm to remove 
(rec) -ssh-rsa                              -- key algorithm to remove 
(rec) !rsa-sha2-256                         -- key algorithm to change (increase modulus size to 3072 bits or larger) 
(rec) !rsa-sha2-512                         -- key algorithm to change (increase modulus size to 3072 bits or larger) 
(rec) -diffie-hellman-group14-sha256        -- kex algorithm to remove 
(rec) -hmac-sha2-256                        -- mac algorithm to remove 
(rec) -hmac-sha2-512                        -- mac algorithm to remove 
(rec) -umac-128@openssh.com                 -- mac algorithm to remove 
(rec) -umac-64-etm@openssh.com              -- mac algorithm to remove 
(rec) -umac-64@openssh.com                  -- mac algorithm to remove 

# additional info
(nfo) For hardening guides on common OSes, please see: <https://www.ssh-audit.com/hardening_guides.html>
(nfo) Be aware that, while this target properly supports the strict key exchange method (via the kex-strict-?-v00@openssh.com marker) needed to protect against the Terrapin vulnerability (CVE-2023-48795), all peers must also support this feature as well, otherwise the vulnerability will still be present.  The following algorithms would allow an unpatched peer to create vulnerable SSH channels with this target: chacha20-poly1305@openssh.com.  If any CBC ciphers are in this list, you may remove them while leaving the *-etm@openssh.com MACs in place; these MACs are fine while paired with non-CBC cipher types.

Joar, das sieht tatsächlich nicht ganz so optimal aus. Ein Hinweis darauf ist also nicht unberechtigt. Ich habe dem Finder also freundlich und dankbar geantwortet, aber auch darauf hingewiesen, dass das System nicht zu meiner Infrastruktur gehört. Zusätzlich habe ich ihm die relevanten Whois-Informationen zur IPv4 des angegebenen Hosts mitgeschickt.

Seine Antwort hat nicht lange auf sich warten lassen:

Thank you for your answer.

Let me know if you need anything else from myside

I hope this type of hard efforts deserves something reward

Hm… „hard efforts“. Ich will das jetzt nicht schlechtreden. Wäre der Hinweis im beruflichen Umfeld angekommen, hätte ich mich vielleicht sogar für eine Kleinigkeit stark gemacht. Aber da es hier nur um meine private Infrastruktur geht – und dann noch mit dem JavaScript-Hinweis und der Meldung zu einem fremden System – wirkt das Ganze doch etwas oberflächlich. Also habe ich ihn freundlich darauf hingewiesen.

Mein Tipp für den Umgang mit solchen Meldungen

Wenn euch mal eine solche Nachricht erreicht: Schnell und freundlich reagieren! Den Report ernst nehmen, bewerten und eine angemessene Rückmeldung geben. Die Mühe des Finders sollte wertgeschätzt werden. Zwei Wochen später mit „Anzeige ist raus!“ zu antworten, wäre der falsche Weg. Denn ganz ehrlich: Es ist für jemanden deutlich aufwendiger, sich die Mühe zu machen, eine Meldung zu schreiben, als einfach das Ganze in ein passendes Darknet-Forum zu posten und dort ein paar XMR oder Bitcoin einzusammeln.

Macht es den Leuten also möglichst einfach, euch zu kontaktieren. Eine security.txt oder klare Kontaktinformationen für eine Security-Mailbox helfen ungemein. Hauptsache, jemand kann seinen Report unkompliziert abgeben – und er wird von jemandem gelesen, der das Ganze bewerten kann.

Hier noch etwas zum klicken für die security.txt:
https://securitytxt.org/
https://de.wikipedia.org/wiki/Security.txt
https://www.allianz-fuer-cybersicherheit.de/Webs/ACS/DE/Home/_/infos/20240430_securitytxt.html

Meine SSH Konfiguration sieht von außen wie folgt aus:

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# general
(gen) banner: SSH-2.0-OpenSSH_9.7 DemMeisterSeinRennAuto
(gen) software: OpenSSH 9.7
(gen) compatibility: OpenSSH 8.5+, Dropbear SSH 2018.76+
(gen) compression: enabled (zlib@openssh.com)
# key exchange algorithms
(kex) sntrup761x25519-sha512@openssh.com -- [info] available since OpenSSH 8.5
(kex) curve25519-sha256 -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
`- [info] default key exchange since OpenSSH 6.4
(kex) curve25519-sha256@libssh.org -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
`- [info] default key exchange since OpenSSH 6.4
(kex) diffie-hellman-group16-sha512 -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) diffie-hellman-group18-sha512 -- [info] available since OpenSSH 7.3
(kex) diffie-hellman-group-exchange-sha256 (3072-bit) -- [info] available since OpenSSH 4.4
`- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 3072. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477).
(kex) ext-info-s -- [info] pseudo-algorithm that denotes the peer supports RFC8308 extensions
(kex) kex-strict-s-v00@openssh.com -- [info] pseudo-algorithm that denotes the peer supports a stricter key exchange method as a counter-measure to the Terrapin attack (CVE-2023-48795)
# host-key algorithms
(key) ssh-ed25519 -- [info] available since OpenSSH 6.5
# encryption algorithms (ciphers)
(enc) aes256-gcm@openssh.com -- [info] available since OpenSSH 6.2
(enc) aes128-gcm@openssh.com -- [info] available since OpenSSH 6.2
(enc) aes256-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) aes192-ctr -- [info] available since OpenSSH 3.7
(enc) aes128-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
# message authentication code algorithms
(mac) hmac-sha2-256-etm@openssh.com -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-512-etm@openssh.com -- [info] available since OpenSSH 6.2
(mac) umac-128-etm@openssh.com -- [info] available since OpenSSH 6.2
# fingerprints
(fin) ssh-ed25519: SHA256:kPRXNCMRLiHfvJunW2CbW5H3NZmn3Wkx2KnHJXl1aLc
# algorithm recommendations (for OpenSSH 9.7)
(rec) +rsa-sha2-256 -- key algorithm to append
(rec) +rsa-sha2-512 -- key algorithm to append
# general (gen) banner: SSH-2.0-OpenSSH_9.7 DemMeisterSeinRennAuto (gen) software: OpenSSH 9.7 (gen) compatibility: OpenSSH 8.5+, Dropbear SSH 2018.76+ (gen) compression: enabled (zlib@openssh.com) # key exchange algorithms (kex) sntrup761x25519-sha512@openssh.com -- [info] available since OpenSSH 8.5 (kex) curve25519-sha256 -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76 `- [info] default key exchange since OpenSSH 6.4 (kex) curve25519-sha256@libssh.org -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62 `- [info] default key exchange since OpenSSH 6.4 (kex) diffie-hellman-group16-sha512 -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73 (kex) diffie-hellman-group18-sha512 -- [info] available since OpenSSH 7.3 (kex) diffie-hellman-group-exchange-sha256 (3072-bit) -- [info] available since OpenSSH 4.4 `- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 3072. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477). (kex) ext-info-s -- [info] pseudo-algorithm that denotes the peer supports RFC8308 extensions (kex) kex-strict-s-v00@openssh.com -- [info] pseudo-algorithm that denotes the peer supports a stricter key exchange method as a counter-measure to the Terrapin attack (CVE-2023-48795) # host-key algorithms (key) ssh-ed25519 -- [info] available since OpenSSH 6.5 # encryption algorithms (ciphers) (enc) aes256-gcm@openssh.com -- [info] available since OpenSSH 6.2 (enc) aes128-gcm@openssh.com -- [info] available since OpenSSH 6.2 (enc) aes256-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52 (enc) aes192-ctr -- [info] available since OpenSSH 3.7 (enc) aes128-ctr -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52 # message authentication code algorithms (mac) hmac-sha2-256-etm@openssh.com -- [info] available since OpenSSH 6.2 (mac) hmac-sha2-512-etm@openssh.com -- [info] available since OpenSSH 6.2 (mac) umac-128-etm@openssh.com -- [info] available since OpenSSH 6.2 # fingerprints (fin) ssh-ed25519: SHA256:kPRXNCMRLiHfvJunW2CbW5H3NZmn3Wkx2KnHJXl1aLc # algorithm recommendations (for OpenSSH 9.7) (rec) +rsa-sha2-256 -- key algorithm to append (rec) +rsa-sha2-512 -- key algorithm to append 
# general
(gen) banner: SSH-2.0-OpenSSH_9.7 DemMeisterSeinRennAuto
(gen) software: OpenSSH 9.7
(gen) compatibility: OpenSSH 8.5+, Dropbear SSH 2018.76+
(gen) compression: enabled (zlib@openssh.com)

# key exchange algorithms
(kex) sntrup761x25519-sha512@openssh.com    -- [info] available since OpenSSH 8.5
(kex) curve25519-sha256                     -- [info] available since OpenSSH 7.4, Dropbear SSH 2018.76
                                            `- [info] default key exchange since OpenSSH 6.4
(kex) curve25519-sha256@libssh.org          -- [info] available since OpenSSH 6.4, Dropbear SSH 2013.62
                                            `- [info] default key exchange since OpenSSH 6.4
(kex) diffie-hellman-group16-sha512         -- [info] available since OpenSSH 7.3, Dropbear SSH 2016.73
(kex) diffie-hellman-group18-sha512         -- [info] available since OpenSSH 7.3
(kex) diffie-hellman-group-exchange-sha256 (3072-bit) -- [info] available since OpenSSH 4.4
                                                      `- [info] OpenSSH's GEX fallback mechanism was triggered during testing. Very old SSH clients will still be able to create connections using a 2048-bit modulus, though modern clients will use 3072. This can only be disabled by recompiling the code (see https://github.com/openssh/openssh-portable/blob/V_9_4/dh.c#L477).
(kex) ext-info-s                            -- [info] pseudo-algorithm that denotes the peer supports RFC8308 extensions
(kex) kex-strict-s-v00@openssh.com          -- [info] pseudo-algorithm that denotes the peer supports a stricter key exchange method as a counter-measure to the Terrapin attack (CVE-2023-48795)

# host-key algorithms
(key) ssh-ed25519                           -- [info] available since OpenSSH 6.5

# encryption algorithms (ciphers)
(enc) aes256-gcm@openssh.com                -- [info] available since OpenSSH 6.2
(enc) aes128-gcm@openssh.com                -- [info] available since OpenSSH 6.2
(enc) aes256-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52
(enc) aes192-ctr                            -- [info] available since OpenSSH 3.7
(enc) aes128-ctr                            -- [info] available since OpenSSH 3.7, Dropbear SSH 0.52

# message authentication code algorithms
(mac) hmac-sha2-256-etm@openssh.com         -- [info] available since OpenSSH 6.2
(mac) hmac-sha2-512-etm@openssh.com         -- [info] available since OpenSSH 6.2
(mac) umac-128-etm@openssh.com              -- [info] available since OpenSSH 6.2

# fingerprints
(fin) ssh-ed25519: SHA256:kPRXNCMRLiHfvJunW2CbW5H3NZmn3Wkx2KnHJXl1aLc

# algorithm recommendations (for OpenSSH 9.7)
(rec) +rsa-sha2-256                         -- key algorithm to append 
(rec) +rsa-sha2-512                         -- key algorithm to append

WordPress wp-cron.php: Ist die angebliche Sicherheitslücke echt?

13. Juni 2024 / / Ein Kommentar
Picture of an hacker checken for wordpress vulnerability

In letzter Zeit begegnen mir immer wieder sogenannte „Vulnerability Report Scams“. Klar, mit Angst und Unwissenheit kann man Geld verdienen – also wird es auch jemand tun. Besonders fällt mir das im Zusammenhang mit der wp-cron.php auf.

Ich habe häufig Reports gesehen, die in etwa so aussehen:

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Critical Vulnerability Report- {Critical BUG #P1} - https://www.example.com/ - vulnerable to attack via wp-cron.php
Hello Security team,
I am a Security Engineer, Cyber Security Researcher, Bug Bounty Hunter & Ethical Hacker. While testing your domain https://www.example.com/ I have found some important vulnerabilities in your site.
Vulnerability Name: https://www.example.com/ - vulnerable to DoS attack via wp-cron.php
Vulnerable Domain: https://www.example.com/wp-cron.php
Description:
The WordPress application is vulnerable to a Denial of Service (DoS) attack via the wp-cron.php script. This script is used by WordPress to perform scheduled tasks, such as publishing scheduled posts, checking for updates, and running plugins.
An attacker can exploit this vulnerability by sending a large number of requests to the wp-cron.php script, causing it to consume excessive resources and overload the server. This can lead to the application becoming unresponsive or crashing, potentially causing data loss and downtime.
I found this vulnerability at https://www.example.com/wp-cron.php endpoint.
Steps to Reproduce: reference- https://hackerone.com/reports/1888723
navigate to: https://www.example.com/wp-cron.php
intercept the request through the burp suite
right click on the request and send it to the repeater
Now send a request, and you will see the response as 200 OK
---
this can be also done by the curl command given below
curl -I "https://www.example.com/wp-cron.php"
POC: Attached
Impact:
If successful, this misconfigured wp-cron.php file can cause lots of damage to the site, such as:
Potential Denial of Service (DoS) attacks, resulting in unavailability of the application.
Server overload and increased resource usage, leading to slow response times or application crashes.
Potential data loss and downtime of the site.
Hackers can exploit the misconfiguration to execute malicious tasks, leading to security breaches.
Exploitation:
Exploitation can be done through a GitHub tool called doser.go https://github.com/Quitten/doser.go
I did not do that as this can impact your website.
Get the doser.py script at https://github.com/Quitten/doser.py
Use this command to run the script: python3 doser.py -t 999 -g 'https://www.example.com/wp-cron.php'
Go after https://www.example.com/ 1000 requests of the doser.py script.
The site returns code 502.
Suggested Mitigation/Remediation Actions:
To mitigate this vulnerability, it is recommended to disable the default WordPress wp-cron.php script and set up a server-side cron job instead. Here are the steps to disable the default wp-cron.php script and set up a server-side cron job:
Access your website's root directory via FTP or cPanel File Manager.
Locate the wp-config.php file and open it for editing.
Add the following line of code to the file, just before the line that says "That's all, stop editing! Happy publishing.":
1define('DISABLE_WP_CRON', true);
Save the changes to the wp-config.php file.
Set up a server-side cron job to run the wp-cron.php script at the desired interval. This can be done using the server's control panel or by editing the server's crontab file.
References:
For more information about this vulnerability, please refer to the following resources:
https://hackerone.com/reports/1888723
https://medium.com/@mayank_prajapati/what-is-wp-cron-php-0dd4c31b0fee
<blockquote class="wp-embedded-content" data-secret="bhpGpkFciz"><a href="https://developer.wordpress.org/plugins/cron/">Cron</a></blockquote><iframe class="wp-embedded-content" sandbox="allow-scripts" security="restricted" style="position: absolute; visibility: hidden;" title="“Cron” — WordPress Developer Resources" src="https://developer.wordpress.org/plugins/cron/embed/#?secret=IPOv13Kdcz#?secret=bhpGpkFciz" data-secret="bhpGpkFciz" width="600" height="338" frameborder="0" marginwidth="0" marginheight="0" scrolling="no"></iframe>
Fix Them
-----
I have protected your company and saved it from a big loss so give me some appreciation Bounty Reward.
I am sharing my PayPal ID with you.
Paypal ID: woop woop
Current Market Value Minimum Bounty Reward for Critical BUG P1 Type.
The bug I reported is part of type P1
Vulnerability severity Bug bounty reward amount (in USD)
P1 (Critical) $2500
P2 (High) $1500
P3 (Medium) $1000
P4 (Low) $500
Please feel free to let me know if you have any other questions or need further information.
I am happy to secure it.
I hope this will be fixed soon. Feel free to let me know if you have any other questions.
Thanks & Regards
Critical Vulnerability Report- {Critical BUG #P1} - https://www.example.com/ - vulnerable to attack via wp-cron.php Hello Security team, I am a Security Engineer, Cyber Security Researcher, Bug Bounty Hunter & Ethical Hacker. While testing your domain https://www.example.com/ I have found some important vulnerabilities in your site. Vulnerability Name: https://www.example.com/ - vulnerable to DoS attack via wp-cron.php Vulnerable Domain: https://www.example.com/wp-cron.php Description: The WordPress application is vulnerable to a Denial of Service (DoS) attack via the wp-cron.php script. This script is used by WordPress to perform scheduled tasks, such as publishing scheduled posts, checking for updates, and running plugins. An attacker can exploit this vulnerability by sending a large number of requests to the wp-cron.php script, causing it to consume excessive resources and overload the server. This can lead to the application becoming unresponsive or crashing, potentially causing data loss and downtime. I found this vulnerability at https://www.example.com/wp-cron.php endpoint. Steps to Reproduce: reference- https://hackerone.com/reports/1888723 navigate to: https://www.example.com/wp-cron.php intercept the request through the burp suite right click on the request and send it to the repeater Now send a request, and you will see the response as 200 OK --- this can be also done by the curl command given below curl -I "https://www.example.com/wp-cron.php" POC: Attached Impact: If successful, this misconfigured wp-cron.php file can cause lots of damage to the site, such as: Potential Denial of Service (DoS) attacks, resulting in unavailability of the application. Server overload and increased resource usage, leading to slow response times or application crashes. Potential data loss and downtime of the site. Hackers can exploit the misconfiguration to execute malicious tasks, leading to security breaches. Exploitation: Exploitation can be done through a GitHub tool called doser.go https://github.com/Quitten/doser.go I did not do that as this can impact your website. Get the doser.py script at https://github.com/Quitten/doser.py Use this command to run the script: python3 doser.py -t 999 -g 'https://www.example.com/wp-cron.php' Go after https://www.example.com/ 1000 requests of the doser.py script. The site returns code 502. Suggested Mitigation/Remediation Actions: To mitigate this vulnerability, it is recommended to disable the default WordPress wp-cron.php script and set up a server-side cron job instead. Here are the steps to disable the default wp-cron.php script and set up a server-side cron job: Access your website's root directory via FTP or cPanel File Manager. Locate the wp-config.php file and open it for editing. Add the following line of code to the file, just before the line that says "That's all, stop editing! Happy publishing.": 1define('DISABLE_WP_CRON', true); Save the changes to the wp-config.php file. Set up a server-side cron job to run the wp-cron.php script at the desired interval. This can be done using the server's control panel or by editing the server's crontab file. References: For more information about this vulnerability, please refer to the following resources: https://hackerone.com/reports/1888723 https://medium.com/@mayank_prajapati/what-is-wp-cron-php-0dd4c31b0fee <blockquote class="wp-embedded-content" data-secret="bhpGpkFciz"><a href="https://developer.wordpress.org/plugins/cron/">Cron</a></blockquote><iframe class="wp-embedded-content" sandbox="allow-scripts" security="restricted" style="position: absolute; visibility: hidden;" title="“Cron” — WordPress Developer Resources" src="https://developer.wordpress.org/plugins/cron/embed/#?secret=IPOv13Kdcz#?secret=bhpGpkFciz" data-secret="bhpGpkFciz" width="600" height="338" frameborder="0" marginwidth="0" marginheight="0" scrolling="no"></iframe> Fix Them ----- I have protected your company and saved it from a big loss so give me some appreciation Bounty Reward. I am sharing my PayPal ID with you. Paypal ID: woop woop Current Market Value Minimum Bounty Reward for Critical BUG P1 Type. The bug I reported is part of type P1 Vulnerability severity Bug bounty reward amount (in USD) P1 (Critical) $2500 P2 (High) $1500 P3 (Medium) $1000 P4 (Low) $500 Please feel free to let me know if you have any other questions or need further information. I am happy to secure it. I hope this will be fixed soon. Feel free to let me know if you have any other questions. Thanks & Regards 
Critical Vulnerability Report- {Critical BUG #P1} - https://www.example.com/ - vulnerable to attack via wp-cron.php

Hello  Security team,

I am a Security Engineer, Cyber Security Researcher, Bug Bounty Hunter  & Ethical Hacker. While testing your domain https://www.example.com/ I have found some important vulnerabilities in your site. 

Vulnerability Name:   https://www.example.com/  -  vulnerable to DoS attack via wp-cron.php

Vulnerable Domain:  https://www.example.com/wp-cron.php

Description: 

The WordPress application is vulnerable to a Denial of Service (DoS) attack via the wp-cron.php script. This script is used by WordPress to perform scheduled tasks, such as publishing scheduled posts, checking for updates, and running plugins.
An attacker can exploit this vulnerability by sending a large number of requests to the wp-cron.php script, causing it to consume excessive resources and overload the server. This can lead to the application becoming unresponsive or crashing, potentially causing data loss and downtime.

I found this vulnerability at https://www.example.com/wp-cron.php endpoint.


Steps to Reproduce: reference- https://hackerone.com/reports/1888723
 
navigate to: https://www.example.com/wp-cron.php
intercept the request through the burp suite
right click on the request and send it to the repeater
Now send a request, and you will see the response as  200 OK

---

this can be also done by the curl command given below

curl -I "https://www.example.com/wp-cron.php"



POC: Attached 

Impact:

If successful, this misconfigured wp-cron.php file can cause lots of damage to the site, such as:

Potential Denial of Service (DoS) attacks, resulting in unavailability of the application.
Server overload and increased resource usage, leading to slow response times or application crashes.
Potential data loss and downtime of the site.
Hackers can exploit the misconfiguration to execute malicious tasks, leading to security breaches.

Exploitation: 
Exploitation can be done through a GitHub tool called doser.go https://github.com/Quitten/doser.go
I did not do that as this can impact your website.
Get the doser.py script at https://github.com/Quitten/doser.py
Use this command to run the script: python3 doser.py -t 999 -g 'https://www.example.com/wp-cron.php'
Go after https://www.example.com/ 1000 requests of the doser.py script.
The site returns code 502.

Suggested Mitigation/Remediation Actions:

To mitigate this vulnerability, it is recommended to disable the default WordPress wp-cron.php script and set up a server-side cron job instead. Here are the steps to disable the default wp-cron.php script and set up a server-side cron job:
Access your website's root directory via FTP or cPanel File Manager.
Locate the wp-config.php file and open it for editing.
Add the following line of code to the file, just before the line that says "That's all, stop editing! Happy publishing.":

1define('DISABLE_WP_CRON', true);

Save the changes to the wp-config.php file.
Set up a server-side cron job to run the wp-cron.php script at the desired interval. This can be done using the server's control panel or by editing the server's crontab file.
References:

For more information about this vulnerability, please refer to the following resources:

https://hackerone.com/reports/1888723

https://medium.com/@mayank_prajapati/what-is-wp-cron-php-0dd4c31b0fee


Cron


Fix Them 

-----

I have protected your company and saved it from a big loss so give me some appreciation Bounty  Reward.

I am sharing my PayPal ID with you.  

Paypal ID:  woop woop


Current  Market  Value Minimum  Bounty  Reward for Critical BUG  P1 Type.    

The bug I reported is part of type P1


 
Vulnerability severity	Bug bounty reward amount (in USD)
P1 (Critical)	$2500
P2 (High)	$1500
P3 (Medium)	$1000
P4 (Low)	$500


Please feel free to let me know if you have any other questions or need further information. 

I am happy to secure it.


I hope this will be fixed soon. Feel free to let me know if you have any other questions.

Thanks & Regards

Ist das nun ein echtes Problem oder nicht?

Nun… Ja und Nein. In der Nachricht wird korrekt beschrieben, was die wp-cron.php tut und warum sie wichtig ist. Auch die Tatsache, dass sie extern unendlich oft aufgerufen werden kann und dadurch potenziell eine Überlastung auslösen könnte, ist nicht falsch. Selbst der Tipp, auf eine lokale Crontab-Version umzusteigen, ist nicht verkehrt. Allerdings muss man das Ganze in den richtigen Kontext setzen: wp-cron.php ist standardmäßig in WordPress aktiviert und wird für geplante Aufgaben genutzt. Die geplanten Aufgaben werden in der Datenbank abgelegt, gibt es etwas zutun und die wp-cron.php wird aufgerufen, dann wird auch gearbeitet, gibt es nichts zutun, dann gibt es auch keine Arbeit. Die Empfehlung, sie zu deaktivieren und durch einen serverseitigen Cron-Job zu ersetzen, ist eher eine Performance-Optimierung als eine echte Sicherheitsmaßnahme.

Es handelt sich hierbei nicht um einen Zero-Day-Exploit und es gibt keine direkte Gefahr eines Datenabflusses. Falls es wirklich zu Performance-Problemen kommt, gibt es einfache Gegenmaßnahmen. Sollte tatsächlich jemand versuchen, die wp-cron.php gezielt anzugreifen, hilft ein simples Rate Limiting – entweder über die Firewall oder direkt mit mod_security (Apache) bzw. limit_req (nginx).

Ein Beispiel für nginx:

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limit_req_zone $binary_remote_addr zone=cronlimit:10m rate=1r/s;
server {
location = /wp-cron.php {
limit_req zone=cronlimit burst=3 nodelay;
limit_req_status 429;
}
}
limit_req_zone $binary_remote_addr zone=cronlimit:10m rate=1r/s; server { location = /wp-cron.php { limit_req zone=cronlimit burst=3 nodelay; limit_req_status 429; } }
limit_req_zone $binary_remote_addr zone=cronlimit:10m rate=1r/s;

server {
    location = /wp-cron.php {
        limit_req zone=cronlimit burst=3 nodelay;
        limit_req_status 429;
    }
}

Das begrenzt die Anfragen auf 1 Anfrage pro Sekunde, mit maximal 3 Anfragen in kurzer Zeit.

Sollte man wp-cron.php einfach deaktivieren?

Nicht unbedingt. Klar, im Fall eines Angriffs kann das als erste Maßnahme helfen. Besser ist es aber, wp-cron.php lokal auszuführen und den Zugriff darauf über den Webserver auf bestimmte IP-Adressen zu beschränken – zum Beispiel die lokale des Webservers. Anschließend kann man einen Cronjob anlegen, der alle 15 Minuten ausgeführt wird:

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*/15 * * * * wget -q -O - https://www.example.com/wp-cron.php?doing_wp_cron >/dev/null 2>&1
*/15 * * * * wget -q -O - https://www.example.com/wp-cron.php?doing_wp_cron >/dev/null 2>&1
*/15 * * * * wget -q -O - https://www.example.com/wp-cron.php?doing_wp_cron >/dev/null 2>&1

Zugriff per nginx einschränken:

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location ~* ^/wp-cron.php$ {
allow 1.2.3.4; # Ersetze mit deiner IP
deny all;
}
location ~* ^/wp-cron.php$ { allow 1.2.3.4; # Ersetze mit deiner IP deny all; }
location ~* ^/wp-cron.php$ {
    allow 1.2.3.4;  # Ersetze mit deiner IP
    deny all;
}

Fazit:

Das ist ganz sicher kein P1-Bug. Und wenn der Report direkt eine Preistabelle mitliefert, ist das schon ein ziemlich eindeutiges Zeichen für einen Scam.

Zusammengefasst:

  • Ja, wp-cron.php könnte unter bestimmten Umständen zu Problemen führen.
  • Nein, es ist kein echter Sicherheits-Bug.
  • Wer weiß, was er tut, hat bereits die richtigen Maßnahmen getroffen.

Also: Keine Panik. Stattdessen lieber kurz die eigene Konfiguration prüfen und gut ist.

Wer auf das nginx Rate Limit setzt und dieses einfach testen möchte, kann das folgende Bash-Script nutzen: rate_limit_test.sh

08-03-2025 kleines Update. Das script ist zu github gewechselt.

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