CVE-2021-25981 Explained : Impact and Mitigation

This article provides an overview of CVE-2021-25981, a vulnerability in Talkyard that allows attackers to reuse an admin's session token, potentially granting them unauthorized access.

Understanding CVE-2021-25981

CVE-2021-25981 is classified as an Insufficient Session Expiration vulnerability in Talkyard, impacting versions v0.2021.20 through v0.2021.33 for regular versions and v0.2021.20 through v0.2021.34 for development versions.

What is CVE-2021-25981?

In Talkyard, the vulnerability allows an attacker to reuse the admin's valid session token, even after logging out. This could lead to the attacker gaining admin privileges if they manage to obtain the token through other means.

The Impact of CVE-2021-25981

With a CVSS base score of 9.8, this critical vulnerability has a high impact on confidentiality, integrity, and availability. Attackers can exploit this issue with low complexity over a network without requiring any user interaction.

Technical Details of CVE-2021-25981

The vulnerability arises from Insufficient Session Expiration in Talkyard, enabling attackers to exploit the system's session handling mechanism.

Vulnerability Description

The vulnerability allows malicious actors to reuse an admin's still-valid session token post-logout, potentially leading to unauthorized access.

Affected Systems and Versions

Talkyard versions v0.2021.20 to v0.2021.33 (regular) and v0.2021.20 to v0.2021.34 (development) are susceptible to this security flaw.

Exploitation Mechanism

Attackers could reuse an admin's session token to gain admin privileges, provided they acquire the token through other theoretical attacks.

Mitigation and Prevention

To secure your system against CVE-2021-25981, it is crucial to take immediate steps, implement long-term security practices, and apply necessary patches and updates.

Immediate Steps to Take

Users are advised to upgrade to version v0.2021.35 to mitigate the vulnerability and prevent unauthorized access.

Long-Term Security Practices

Incorporating robust session management and access control mechanisms can enhance the overall security posture of the system.

Patching and Updates

Regularly applying security patches and updates provided by the vendor is essential to address known vulnerabilities and protect the system from potential exploitation.