CVE-2021-37659 : Exploit Details and Defense Strategies

TensorFlow is an end-to-end open source platform for machine learning. In affected versions, an attacker can cause undefined behavior via binding a reference to null pointer in all binary cwise operations that don't require broadcasting. This vulnerability, assigned CVE-2021-37659, has a CVSS base score of 7.3, indicating a high severity issue with a low attack complexity.

Understanding CVE-2021-37659

This section provides an in-depth look at the vulnerability in TensorFlow.

What is CVE-2021-37659?

CVE-2021-37659 is an out-of-bounds read vulnerability caused by a null pointer dereference in TensorFlow. The issue allows an attacker to trigger heap out-of-bounds reads and undefined behavior by binding a reference to a null pointer.

The Impact of CVE-2021-37659

The impact of this vulnerability is classified as high, with confidentiality impact and availability impact both rated as high. Attackers can exploit this issue in affected versions to cause undefined behavior and potentially execute arbitrary code.

Technical Details of CVE-2021-37659

This section delves into the specifics of the vulnerability within TensorFlow.

Vulnerability Description

The vulnerability arises due to the assumption that two inputs in binary cwise operations have the same number of elements but lack proper validation checks. Consequently, the eigen functor triggers heap out-of-bounds reads and undefined behavior.

Affected Systems and Versions

TensorFlow versions >= 2.3.4 and < 2.5.1 are impacted by this vulnerability. Specifically, versions 2.5.0, 2.4.0, 2.4.1, 2.4.2, 2.4.3, and 2.3.4 are vulnerable to this issue.

Exploitation Mechanism

To exploit this vulnerability, an attacker needs local access to the target system. By binding a reference to a null pointer in certain cwise operations, the attacker can trigger the vulnerability and potentially execute malicious code.

Mitigation and Prevention

This section outlines the steps to mitigate and prevent exploitation of CVE-2021-37659.

Immediate Steps to Take

Users are advised to apply the patched updates provided by TensorFlow. It is crucial to update to TensorFlow 2.6.0 or apply the specific fixes included in versions 2.5.1, 2.4.3, and 2.3.4.

Long-Term Security Practices

Practicing good security hygiene, such as regular software updates and monitoring security advisories, can help mitigate the risks posed by such vulnerabilities.

Patching and Updates

To address CVE-2021-37659, users should promptly install the recommended patches and updates released by TensorFlow to eliminate the vulnerability.