sharutils: Insecure temporary file creation
Gentoo Linux Security Advisory
||GLSA 200504-06 / sharutils
||April 06, 2005
||April 06, 2005: 01
All supported architectures
The unshar utility is vulnerable to symlink attacks, potentially allowing a
local user to overwrite arbitrary files.
sharutils is a collection of tools to deal with shar archives.
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.
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.
There is no known workaround at this time.
All sharutils users should upgrade to the latest version:
Code Listing 3.1: Resolution
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-arch/sharutils-4.2.1-r11"