fluent/fluentd · Security
ReDoS vulnerability in parser_apache2
- GHSA ID
- GHSA-hwhf-64mh-r662
- CVE ID
- CVE-2021-41186
- Severity
- medium
- Published
- Updated
- CVSS
- 5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CVSS v3
- 5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
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_PLUGINor--pluginoption of fluentd).
References
CWEs
- CWE-400 · Uncontrolled Resource Consumption
References
- https://github.com/fluent/fluentd/security/advisories/GHSA-hwhf-64mh-r662 ↗
- https://github.com/fluent/fluentd/blob/master/CHANGELOG.md#v1142 ↗
- https://github.com/github/securitylab-vulnerabilities/blob/52dc4a2a828c6dc24231967c2937ad92038184a9/vendor_reports/GHSL-2021-102-fluent-fluentd.md ↗
- https://nvd.nist.gov/vuln/detail/CVE-2021-41186 ↗
- https://github.com/fluent/fluentd/commit/5482a3d049dab351de0be68f4b4bc562319d8511 ↗
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/fluentd/CVE-2021-41186.yml ↗
- https://github.com/advisories/GHSA-hwhf-64mh-r662 ↗