// For flags

CVE-2021-43821

Files Accessible to External Parties in Opencast

Severity Score

7.7
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

2
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

Opencast is an Open Source Lecture Capture & Video Management for Education. Opencast before version 9.10 or 10.6 allows references to local file URLs in ingested media packages, allowing attackers to include local files from Opencast's host machines and making them available via the web interface. Before Opencast 9.10 and 10.6, Opencast would open and include local files during ingests. Attackers could exploit this to include most local files the process has read access to, extracting secrets from the host machine. An attacker would need to have the privileges required to add new media to exploit this. But these are often widely given. The issue has been fixed in Opencast 10.6 and 11.0. You can mitigate this issue by narrowing down the read access Opencast has to files on the file system using UNIX permissions or mandatory access control systems like SELinux. This cannot prevent access to files Opencast needs to read though and we highly recommend updating.

Opencast es un software de código abierto para la captura de conferencias y la administración de vídeo para la educación. Opencast versiones anteriores a 9.10 o 10.6, permite referencias a URLs de archivos locales en paquetes de medios ingeridos, permitiendo a atacantes incluir archivos locales de las máquinas anfitrionas de Opencast y hacerlos disponibles por medio de la interfaz web. En versiones anteriores a Opencast 9.10 y 10.6, Opencast abría e incluía archivos locales durante las ingestas. Los atacantes podían aprovechar esto para incluir la mayoría de los archivos locales a los que el proceso tuviera acceso de lectura, extrayendo secretos de la máquina anfitriona. Un atacante necesitaría tener los privilegios necesarios para añadir nuevos medios para explotar esto. Sin embargo, estos suelen ser ampliamente otorgados. El problema se ha corregido en Opencast versiones 10.6 y 11.0. Puede mitigar este problema limitando el acceso de lectura que Opencast posee a los archivos del sistema de archivos mediante permisos UNIX o sistemas de control de acceso obligatorios como SELinux. Sin embargo, esto no puede impedir el acceso a los archivos que Opencast necesita leer, por lo que recomendamos encarecidamente la actualización

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
Low
Authentication
Single
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-11-16 CVE Reserved
  • 2021-12-14 CVE Published
  • 2021-12-27 First Exploit
  • 2024-03-07 EPSS Updated
  • 2024-08-04 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-552: Files or Directories Accessible to External Parties
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Apereo
Search vendor "Apereo"
Opencast
Search vendor "Apereo" for product "Opencast"
< 10.6
Search vendor "Apereo" for product "Opencast" and version " < 10.6"
-
Affected