Improper Verification of Cryptographic Signature in SimpleSAMLphp SimpleSAMLphp

1) Improper Verification of Cryptographic Signature

EUVDB-ID: #VU31345

Risk: High

CVSSv4.0: 7.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-7711

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

Exploit availability: No

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

HTTPRedirect.php in the saml2 library in SimpleSAMLphp before 1.15.4 has an incorrect check of return values in the signature validation utilities, allowing an attacker to get invalid signatures accepted as valid by forcing an error during validation. This occurs because of a dependency on PHP functionality that interprets a -1 error code as a true boolean value.

Mitigation

Install update from vendor's website.

Vulnerable software versions

SimpleSAMLphp: 1.15.0 - 1.15.3

CPE2.3

• cpe:2.3:a:simplesamlphp:simplesamlphp:1.15.0:*:*:*:*:*:*:*
• cpe:2.3:a:simplesamlphp:simplesamlphp:1.15.1:*:*:*:*:*:*:*
• cpe:2.3:a:simplesamlphp:simplesamlphp:1.15.2:*:*:*:*:*:*:*

External links

https://github.com/simplesamlphp/saml2/commit/4f6af7f69f29df8555a18b9bb7b646906b45924d
https://lists.debian.org/debian-lts-announce/2018/03/msg00017.html
https://simplesamlphp.org/security/201803-01

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.