Race condition in gzip 1.2.4, 1.3.3, and earlier, when decompressing a gzipped file, allows local users to modify permissions of arbitrary files via a hard link attack on a file while it is being decompressed, whose permissions are changed by gzip after the decompression is complete.

New gzip packages are available for Slackware 8.1, 9.0, 9.1, 10.0, 10.1, 10.2, and -current to fix possible security issues.

The remote host is running Apple Mac OS X, but lacks Security Update 2006-004.

This security update contains fixes for the following applications :

AFP Server Bluetooth Bom DHCP dyld fetchmail gnuzip ImageIO LaunchServices OpenSSH telnet WebKit

An updated gzip package is now available.

This update has been rated as having low security impact by the Red Hat Security Response Team.

The gzip package contains the GNU gzip data compression program.

A bug was found in the way zgrep processes file names. If a user can be tricked into running zgrep on a file with a carefully crafted file name, arbitrary commands could be executed as the user running zgrep.
The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2005-0758 to this issue.

A bug was found in the way gunzip modifies permissions of files being decompressed. A local attacker with write permissions in the directory in which a victim is decompressing a file could remove the file being written and replace it with a hard link to a different file owned by the victim. gunzip then gives the linked file the permissions of the uncompressed file. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2005-0988 to this issue.

A directory traversal bug was found in the way gunzip processes the -N flag. If a victim decompresses a file with the -N flag, gunzip fails to sanitize the path which could result in a file owned by the victim being overwritten. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2005-1228 to this issue.

Users of gzip should upgrade to this updated package, which contains backported patches to correct these issues.

Imran Ghory discovered a race condition in the file permission restore code of gzip and gunzip. While a user was compressing or decompressing a file, a local attacker with write permissions in the directory of that file could replace the target file with a hard link. This would cause gzip to restore the file permissions to the hard link target instead of to the gzip output file, which could be exploited to gain read or even write access to files of other users. (CAN-2005-0988)

Ulf Harnhammar found a path traversal vulnerability when gunzip was used with the -N option. An attacker could exploit this to create files in an arbitrary directory with the permissions of a user if he tricked this user to decompress a specially crafted gzip file using the -N option (which can also happen in systems that automatically process uploaded gzip files). (CAN-2005-1228).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Problem Description Two problems related to extraction of files exist in gzip :

The first problem is that gzip does not properly sanitize filenames containing '/' when uncompressing files using the -N command line option.

The second problem is that gzip does not set permissions on newly extracted files until after the file has been created and the file descriptor has been closed. Impact The first problem can allow an attacker to overwrite arbitrary local files when uncompressing a file using the -N command line option.

The second problem can allow a local attacker to change the permissions of arbitrary local files, on the same partition as the one the user is uncompressing a file on, by removing the file the user is uncompressing and replacing it with a hardlink before the uncompress operation is finished. Workaround Do not use the -N command line option on untrusted files and do not uncompress files in directories where untrusted users have write access.

Two problems have been discovered in gzip, the GNU compression utility. The Common Vulnerabilities and Exposures project identifies the following problems.

  - CAN-2005-0988     Imran Ghory discovered a race condition in the     permissions setting code in gzip. When decompressing a     file in a directory an attacker has access to, gunzip     could be tricked to set the file permissions to a     different file the user has permissions to.

  - CAN-2005-1228

    Ulf Harnhammar discovered a path traversal     vulnerability in gunzip. When gunzip is used with the -N     option an attacker could use this vulnerability to     create files in an arbitrary directory with the     permissions of the user.

The remote Redhat Enterprise Linux 4 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2005:357 advisory.

  - security flaw (CVE-2005-0758, CVE-2005-0988, CVE-2005-1228)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Several vulnerabilities have been discovered in the gzip package :

Zgrep in gzip before 1.3.5 does not properly sanitize arguments, which allows local users to execute arbitrary commands via filenames that are injected into a sed script. (CVE-2005-0758)

A race condition in gzip 1.2.4, 1.3.3, and earlier when decompressing a gzip file allows local users to modify permissions of arbitrary files via a hard link attack on a file while it is being decompressed, whose permissions are changed by gzip after the decompression is complete. (CVE-2005-0988)

A directory traversal vulnerability via 'gunzip -N' in gzip 1.2.4 through 1.3.5 allows remote attackers to write to arbitrary directories via a .. (dot dot) in the original filename within a compressed file. (CVE-2005-1228)

Updated packages are patched to address these issues.

The remote host is affected by the vulnerability described in GLSA-200505-05 (gzip: Multiple vulnerabilities)

    The gzip and gunzip programs are vulnerable to a race condition     when setting file permissions (CAN-2005-0988), as well as improper     handling of filename restoration (CAN-2005-1228). The zgrep utility     improperly sanitizes arguments, which may come from an untrusted source     (CAN-2005-0758).
  Impact :

    These vulnerabilities could allow arbitrary command execution,     changing the permissions of arbitrary files, and installation of files     to an aribitrary location in the filesystem.
  Workaround :

    There is no known workaround at this time.

ID	Name	Product	Family	Severity
22421	Slackware 10.0 / 10.1 / 10.2 / 8.1 / 9.0 / 9.1 / current : gzip (SSA:2006-262-01)	Nessus	Slackware Local Security Checks	high
22125	Mac OS X Multiple Vulnerabilities (Security Update 2006-004)	Nessus	MacOS X Local Security Checks	critical
21810	CentOS 3 / 4 : gzip (CESA-2005:357)	Nessus	CentOS Local Security Checks	medium
20504	Ubuntu 4.10 / 5.04 : gzip vulnerabilities (USN-116-1)	Nessus	Ubuntu Local Security Checks	medium
18960	FreeBSD : gzip -- directory traversal and permission race vulnerabilities (63bd4bad-dffe-11d9-b875-0001020eed82)	Nessus	FreeBSD Local Security Checks	medium
18673	Debian DSA-752-1 : gzip - several vulnerabilities	Nessus	Debian Local Security Checks	medium
18469	RHEL 4 : gzip (RHSA-2005:357)	Nessus	Red Hat Local Security Checks	high
18308	Mandrake Linux Security Advisory : gzip (MDKSA-2005:092)	Nessus	Mandriva Local Security Checks	medium
18231	GLSA-200505-05 : gzip: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	medium

Detections

Analytics

CVE-2005-0988

medium

Tenable Plugins

high

critical

medium

medium

medium

medium

high

medium

medium