Information disclosure in Debian Linux - CVE-2017-2624

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Main Vulnerability Database Vulnerabilities #VU36813

Information disclosure in Debian Linux - CVE-2017-2624

Published: July 27, 2018 / Updated: August 8, 2020


Vulnerability identifier: #VU36813
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2017-2624
CWE-ID: CWE-200
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local authenticated user to execute arbitrary code.

It was found that xorg-x11-server before 1.19.0 including uses memcmp() to check the received MIT cookie against a series of valid cookies. If the cookie is correct, it is allowed to attach to the Xorg session. Since most memcmp() implementations return after an invalid byte is seen, this causes a time difference between a valid and invalid byte, which could allow an efficient brute force attack.


Affected software

Debian Linux
Gentoo Linux
Fedora
nx-libs
x2goserver

How to mitigate CVE-2017-2624

Install update from vendor's website.

nx-libs - addressed in versions 3.5.0.33-1.el6, 3.5.0.33-1.fc25, 3.5.0.33-4.fc26, 3.5.0.33-4.fc27
x2goserver - addressed in versions 4.0.1.21-1.el6, 4.0.1.21-1.fc25, 4.0.1.22-2.fc26, 4.0.1.22-2.fc27

External References

Related Security Bulletins