Heap-based Buffer Overflow Affecting rsyslog-mmjsonparse 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 ID SNYK-CENTOS8-RSYSLOGMMJSONPARSE-2034471
  • published 26 Jul 2021
  • disclosed 1 Oct 2019

How to fix?

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

NVD Description

Note: Versions mentioned in the description apply only to the upstream rsyslog-mmjsonparse package and not the rsyslog-mmjsonparse 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
Expand this section

NVD

9.8 critical
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High