OpenSSL, Groff: Insecure tempfile handling

Background

OpenSSL is a toolkit implementing the Secure Sockets Layer and Transport Layer Security protocols as well as a general-purpose cryptography library. It includes the der_chop script, which is used to convert DER-encoded certificates to PEM format. Groff (GNU Troff) is a typesetting package which reads plain text mixed with formatting commands and produces formatted output. It includes groffer, a command used to display groff files and man pages on X and tty.

Description

groffer and the der_chop script create temporary files in world-writeable directories 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 groffer or der_chop 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 Groff users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose sys-apps/groff

All OpenSSL users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=dev-libs/openssl-0.9.7d-r2"

Note: /etc/ssl/misc/der_chop is protected by Portage as a configuration file. Don’t forget to use etc-update and overwrite the old version with the new one.