SB2018072721 - Information disclosure in Debian Linux
Published: July 27, 2018 Updated: August 8, 2020
Security Bulletin ID
SB2018072721
Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Information disclosure (CVE-ID: CVE-2017-2624)
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.
Remediation
Install update from vendor's website.
References
- http://www.securityfocus.com/bid/96480
- http://www.securitytracker.com/id/1037919
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2624
- https://gitlab.freedesktop.org/xorg/xserver/commit/d7ac755f0b618eb1259d93c8a16ec6e39a18627c
- https://lists.debian.org/debian-lts-announce/2017/11/msg00032.html
- https://security.gentoo.org/glsa/201704-03
- https://security.gentoo.org/glsa/201710-30
- https://www.x41-dsec.de/lab/advisories/x41-2017-001-xorg/