Heap-based Buffer Overflow Affecting rsyslog-gssapi package, versions <0:8.1911.0-3.el8


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.81% (83rd percentile)

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  • Snyk IDSNYK-CENTOS8-RSYSLOGGSSAPI-2034322
  • published26 Jul 2021
  • disclosed1 Oct 2019

Introduced: 1 Oct 2019

CVE-2019-17042  (opens in a new tab)
CWE-122  (opens in a new tab)

How to fix?

Upgrade Centos:8 rsyslog-gssapi to version 0:8.1911.0-3.el8 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rsyslog-gssapi package and not the rsyslog-gssapi package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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 Scores

version 3.1