#VU35033 Input validation error in Debian Linux - CVE-2011-4120

Vulnerability identifier: #VU35033

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2011-4120

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Debian Linux
Operating systems & Components / Operating system

Vendor: Debian

Description

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

Yubico PAM Module before 2.10 performed user authentication when 'use_first_pass' PAM configuration option was not used and the module was configured as 'sufficient' in the PAM configuration. A remote attacker could use this flaw to circumvent common authentication process and obtain access to the account in question by providing a NULL value (pressing Ctrl-D keyboard sequence) as the password string.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Debian Linux: 8.0 - 9.0

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External links
https://access.redhat.com/security/cve/cve-2011-4120
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2011-4120
https://security-tracker.debian.org/tracker/CVE-2011-4120
https://www.openwall.com/lists/oss-security/2011/11/07/6

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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.