ReDoS vulnerability in parser_apache2
CVE-2021-41186

5.9MEDIUM

Key Information:

Vendor

Fluent

Status
Fluentd
Vendor
CVE Published:
29 October 2021

What is CVE-2021-41186?

Fluentd collects events from various data sources and writes them to files to help unify logging infrastructure. The 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. This issue is patched in version 1.14.2 There are two workarounds available. Either don't use parser_apache2 for parsing logs (which cannot guarantee generated by Apache), or 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).

Affected Version(s)

fluentd >= 0.14.14, < 1.14.2

References

https://github.com/fluent/fluentd/security/advisories/GHS...
x_refsource_CONFIRM
https://github.com/fluent/fluentd/blob/master/CHANGELOG.m...
x_refsource_MISC
https://github.com/github/securitylab-vulnerabilities/blo...
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CVSS V3.1

Score:
5.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2021-41186 : ReDoS vulnerability in parser_apache2