Vulnerability identifier: #VU31345

Vulnerability risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-7711

CWE-ID: CWE-347

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
SimpleSAMLphp
Web applications / Other software

Vendor: SimpleSAMLphp

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

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

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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.