Launch Week Day 1: Announcing Security Design Review
MEDIUM 5.9 RubyGems

ReDoS vulnerability in parser_apache2

GHSA-hwhf-64mh-r662 · BIT-fluentd-2021-41186 · CVE-2021-41186

Published · Modified

Description

Impact

parser_apache2 plugin in Fluentd v0.14.14 to v1.14.1 suffers from a regular expression denial of service (ReDoS) vulnerability. A broken apache log with a certain pattern of string can spend too much time in a regular expression, resulting in the potential for a DoS attack.

Patches

v1.14.2

Workarounds

Either of the following:

  • Don't use parser_apache2 for parsing logs which cannot guarantee generated by Apache.
  • Put patched version of parser_apache2.rb into /etc/fluent/plugin directory (or any other directories specified by the environment variable FLUENT_PLUGIN or --plugin option of fluentd).

References

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