Detections
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Debian DSA-030-2 : xfree86
high Nessus Plugin ID 14867
Synopsis
The remote Debian host is missing a security-related update.Description
Chris Evans, Joseph S. Myers, Michal Zalewski, Alan Cox, and others have noted a number of problems in several components of the X Window System sample implementation (from which XFree86 is derived). While there are no known reports of real-world malicious exploits of any of these problems, it is nevertheless suggested that you upgrade your XFree86 packages immediately.The scope of this advisory is XFree86 3.3.6 only, since that is the version released with Debian GNU/Linux 2.2 ('potato'); Debian packages of XFree86 4.0 and later have not been released as part of a Debian distribution.
Several people are responsible for authoring the fixes to these problems, including Aaron Campbell, Paulo Cesar Pereira de Andrade, Keith Packard, David Dawes, Matthieu Herrb, Trevor Johnson, Colin Phipps, and Branden Robinson.
- The X servers are vulnerable to a denial-of-service attack during XC-SECURITY protocol negotiation.
- X clients based on Xlib (which is most of them) are subject to potential buffer overflows in the _XReply() and _XAsyncReply() functions if they connect to a maliciously-coded X server that places bogus data in its X protocol replies. NOTE: This is only an effective attack against X clients running with elevated privileges (setuid or setgid programs), and offers potential access only to the elevated privilege. For instance, the most common setuid X client is probably xterm. On many Unix systems, xterm is setuid root; in Debian 2.2, xterm is only setgid utmp, which means that an effective exploit is limited to corruption of the lastlog, utmp, and wtmp files --not general root access.
Also note that the attacker must already have sufficient privileges to start such an X client and successfully connect to the X server.
- There is a buffer overflow (not stack-based) in xdm's XDMCP code.
- There is a one-byte overflow in Xtrans.c.
- Xtranssock.c is also subject to buffer overflow problems.
- There is a buffer overflow with the -xkbmap X server flag.
- The MultiSrc widget in the Athena widget library handle temporary files insecurely.
- The imake program handles temporary files insecurely when executing install rules.
- The ICE library is subject to buffer overflow attacks.
- The xauth program handles temporary files insecurely.
- The XauLock() function in the Xau library handles temporary files insecurely.
- The gccmakedep and makedepend programs handle temporary files insecurely.
All of the above issues are resolved by this security release.
There are several other XFree86 security issues commonly discussed in conjunction with the above, to which an up-to-date Debian 2.2 system isNOT vulnerable :
- There are 4 distinct problems with Xlib's XOpenDisplay() function in which a maliciously coded X server could cause a denial-of-service attack or buffer overflow. As before, this is only an effective attack against X clients running with elevated privileges, and the attacker must already have sufficient privileges to start such an X client and successfully connect to the X server. Debian 2.2 and 2.2r1 are only vulnerable to one of these problems, because we applied patches to XFree86 3.3.6 to correct the other three. An additional patch applied for Debian 2.2r2 corrected the fourth.
- The AsciiSrc widget in the Athena widget library handles temporary files insecurely. Debian 2.2r2 is not vulnerable to this problem because we applied a patch to correct it.
- The imake program uses mktemp() instead of mkstemp().
This problem does not exist in XFree86 3.3.6, and therefore no release of Debian 2.2 is affected.
These problems have been fixed in version 3.3.6-11potato32 and we recommend that you upgrade your X packages immediately.
Solution
Upgrade the affected xfree86 package.See Also
Plugin Details
Severity: High
ID: 14867
File Name: debian_DSA-030.nasl
Version: 1.24
Type: local
Agent: unix
Family: Debian Local Security Checks
Published: 9/29/2004
Updated: 1/4/2021
Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus
Vulnerability Information
CPE: p-cpe:/a:debian:debian_linux:xfree86, cpe:/o:debian:debian_linux:2.2
Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l
Exploit Ease: No known exploits are available
Patch Publication Date: 2/12/2001
Reference Information
DSA: 030