CVE-2020-27743 : Security Advisory and Response

libtac in pam_tacplus through 1.5.1 lacks a check for a failure of RAND_bytes()/RAND_pseudo_bytes. This could lead to the use of a non-random/predictable session_id.

Understanding CVE-2020-27743

libtac in pam_tacplus through 1.5.1 is vulnerable to a lack of check for failure of RAND_bytes()/RAND_pseudo_bytes, potentially resulting in the use of a non-random or predictable session_id.

What is CVE-2020-27743?

This CVE refers to a vulnerability in libtac in pam_tacplus through version 1.5.1, where a crucial check for the failure of RAND_bytes()/RAND_pseudo_bytes is missing, allowing the use of a non-random or predictable session_id.

The Impact of CVE-2020-27743

The impact of this vulnerability is the potential use of non-random or predictable session IDs, which can lead to security compromises and unauthorized access.

Technical Details of CVE-2020-27743

libtac in pam_tacplus through version 1.5.1 is susceptible to the following technical details:

Vulnerability Description

The vulnerability arises from the absence of a check for the failure of RAND_bytes()/RAND_pseudo_bytes, enabling the use of non-random or predictable session IDs.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions: All versions up to and including 1.5.1 are affected.

Exploitation Mechanism

The lack of validation for the randomness of session IDs can be exploited by attackers to predict or manipulate session IDs, potentially leading to unauthorized access.

Mitigation and Prevention

To address CVE-2020-27743, consider the following mitigation strategies:

Immediate Steps to Take

Update to the latest version of pam_tacplus to mitigate the vulnerability.
Monitor for any unusual or unauthorized access attempts.

Long-Term Security Practices

Implement regular security audits and code reviews to identify and address vulnerabilities promptly.
Enhance randomization techniques for session IDs to prevent predictability.

Patching and Updates

Apply patches and updates provided by the vendor to fix the vulnerability and enhance system security.