GLSA 200504-06: sharutils: Insecure temporary file creation

http://security.gentoo.org/

Severity:	normal
Title:	sharutils: Insecure temporary file creation
Date:	04/06/2005
Bugs:	#87939
ID:	200504-06

Synopsis

The unshar utility is vulnerable to symlink attacks, potentially allowing a local user to overwrite arbitrary files.

Background

sharutils is a collection of tools to deal with shar archives.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
app-arch/sharutils	< 4.2.1-r11	>= 4.2.1-r11	All supported architectures

Description

Joey Hess has discovered that the program unshar, which is a part of sharutils, creates temporary files in a world-writable directory with predictable names.

Impact

A local attacker could create symbolic links in the temporary files directory, pointing to a valid file somewhere on the filesystem. When unshar is executed, this would result in the file being overwritten with the rights of the user running the utility, which could be the root user.

Workaround

There is no known workaround at this time.

Resolution

All sharutils users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=app-arch/sharutils-4.2.1-r11"

References

Ubuntu Advisory

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-200504-06.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.