CVE-2019-17042

Public on 2019-10-07
Modified on 2020-07-01
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.
Severity
Medium severity
Medium
CVSS v3 Base Score
7.5
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2 - Core rsyslog 2020-06-26 ALAS2-2020-1447 Fixed

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD CVSSv3 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD CVSSv2 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P