// For flags

CVE-2021-41186

ReDoS vulnerability in parser_apache2

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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).

Fluentd recoge eventos de varias fuentes de datos y los escribe en archivos para ayudar a unificar la infraestructura de registro. El plugin parser_apache2 en Fluentd versiones v0.14.14 hasta v1.14.1 sufre una vulnerabilidad de denegación de servicio de expresión regular (ReDoS). Un registro de apache roto con un determinado patrón de cadena puede pasar demasiado tiempo en una expresión regular, resultando en un potencial de un ataque DoS. Este problema está parcheado en la versión 1.14.2. Se presentan dos soluciones disponibles. O bien no usar parser_apache2 para analizar los registros (que no pueden ser garantizados por Apache), o poner la versión parcheada de parser_apache2.rb en el directorio /etc/fluent/plugin (o cualquier otro directorio especificado por la variable de entorno "FLUENT_PLUGIN" o "--plugin" de fluentd)

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-09-15 CVE Reserved
  • 2021-10-29 CVE Published
  • 2024-07-14 EPSS Updated
  • 2024-08-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-400: Uncontrolled Resource Consumption
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Fluentd
Search vendor "Fluentd"
 Fluentd
Search vendor "Fluentd" for product "Fluentd"
 >= 0.14.14 <= 1.14.1
Search vendor "Fluentd" for product "Fluentd" and version " >= 0.14.14 <= 1.14.1"
-
Affected