CVE-2019-17042 Information

Description

An issue was discovered in Rsyslog v8.1908.0. contrib/pmcisconames/pmcisconames.c has a heap overflow in the parser for Cisco log messages. The parser tries to locate a log message delimiter (in this case a space or a colon) but fails to account for strings that do not satisfy this constraint. If the string does not match then the variable lenMsg will reach the value zero and will skip the sanity check that detects invalid log messages. The message will then be considered valid and the parser will eat up the nonexistent colon delimiter. In doing so it will decrement lenMsg a signed integer whose value was zero and now becomes minus one. The following step in the parser is to shift left the contents of the message. To do this it will call memmove with the right pointers to the target and destination strings but the lenMsg will now be interpreted as a huge value causing a heap overflow.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Reference

http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00031.html http://lists.opensuse.org/opensuse-security-announce/2019-11/msg00032.html https://github.com/rsyslog/rsyslog/blob/v8-stable/ChangeLog https://github.com/rsyslog/rsyslog/pull/3883 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KPNCHI7X2IEXRH6RYD6IDPR4PLB5RPC7/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/W6SUQE25RD37CD24BHKUWMG27U5RQ2FU/

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

9.8