CVE-2022-24903

/// Technical description

Rsyslog is a rocket-fast system for log processing. Modules for TCP syslog reception have a potential heap buffer overflow when octet-counted framing is used. This can result in a segfault or some other malfunction. As of our understanding, this vulnerability can not be used for remote code execution. But there may still be a slight chance for experts to do that. The bug occurs when the octet count is read. While there is a check for the maximum number of octets, digits are written to a heap buffer even when the octet count is over the maximum, This can be used to overrun the memory buffer. However, once the sequence of digits stop, no additional characters can be added to the buffer. In our opinion, this makes remote exploits impossible or at least highly complex. Octet-counted framing is one of two potential framing modes. It is relatively uncommon, but enabled by default on receivers. Modules `imtcp`, `imptcp`, `imgssapi`, and `imhttp` are used for regular syslog message reception.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References