rsyncd vulnerabilities

1/28/02
CAN 2002-0048

Impact

This vulnerability could be exploited by a remote attacker to execute arbitrary commands with root privileges.

Note: The red stoplight on this page indicates the highest possible severity level for this category of vulnerabilities. The actual severity level for this instance is indicated by the colored dot beside the link to this tutorial on the previous page.

Background

rsync is a Unix protocol for synchronizing files across a network. By using an algorithm which transmits only the differences between remote files instead of the files themselves, rsync is able to synchronize files much more efficiently than other protocols.

The Problem

Due to the inappropriate use of user-supplied signed integers as an array index, it is possible for a remote attacker to write null bytes to arbitrary memory locations. This condition could be exploited by a remote attacker, leading to corruption of the stack and possible execution of arbitrary code.

Versions of rsync prior to 2.5.2 are affected by this vulnerability, unless a fixed release has already been installed.

Resolution

Upgrade to rsync 2.5.2 or higher, or install a fixed release from your vendor. Vendor fixes are available for SuSE, Engarde, Connectiva, Red Hat, Debian, and Trustix.

Where can I read more about this?

This vulnerability was first announced in SuSE Security Announcement 2002:004.