CVE-2021-31535 Information

Description

LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code. The libX11 XLookupColor request (intended for server-side color lookup) contains a flaw allowing a client to send color-name requests with a name longer than the maximum size allowed by the protocol (and also longer than the maximum packet size for normal-sized packets). The user-controlled data exceeding the maximum size is then interpreted by the server as additional X protocol requests and executed e.g. to disable X server authorization completely. For example if the victim encounters malicious terminal control sequences for color codes then the attacker may be able to take full control of the running graphical session.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Reference

https://unparalleled.eu/blog/2021/20210518-using-xterm-to-navigate-the-huge-color-space/ https://unparalleled.eu/publications/2021/advisory-unpar-2021-1.txt https://lists.freedesktop.org/archives/xorg/ https://www.openwall.com/lists/oss-security/2021/05/18/2 https://www.openwall.com/lists/oss-security/2021/05/18/3 https://lists.x.org/archives/xorg-announce/2021-May/003088.html https://lists.debian.org/debian-lts-announce/2021/05/msg00021.html http://packetstormsecurity.com/files/162737/libX11-Insufficient-Length-Check-Injection.html https://www.debian.org/security/2021/dsa-4920 http://www.openwall.com/lists/oss-security/2021/05/18/2 https://security.gentoo.org/glsa/202105-16 http://seclists.org/fulldisclosure/2021/May/52 https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/8d2e02ae650f00c4a53deb625211a0527126c605 https://security.netapp.com/advisory/ntap-20210813-0001/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TEOT4RLB76RVPJQKGGTIKTBIOLHX2NR6/ https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc@%3Cusers.kafka.apache.org%3E https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc@%3Cdev.kafka.apache.org%3E https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7@%3Cusers.kafka.apache.org%3E https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7@%3Cdev.kafka.apache.org%3E

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

9.8