CVE-2021-28089 : Exploit Details and Defense Strategies

Tor before 0.4.5.7 allows a remote participant in the Tor directory protocol to exhaust CPU resources on a target, aka TROVE-2021-001.

Understanding CVE-2021-28089

This CVE affects Tor versions prior to 0.4.5.7, enabling a remote attacker to consume excessive CPU resources on a targeted system.

What is CVE-2021-28089?

CVE-2021-28089, also known as TROVE-2021-001, is a vulnerability found in Tor's directory protocol. It allows a malicious user to disrupt the target's normal operation by causing a CPU exhaustion attack.

The Impact of CVE-2021-28089

The impact of this vulnerability is significant as it can lead to denial of service (DoS) conditions on the target system. By exploiting this issue, an attacker can disrupt the availability of Tor services and cause resource exhaustion on the affected machine.

Technical Details of CVE-2021-28089

Detailed technical information regarding the vulnerability.

Vulnerability Description

The vulnerability in Tor before version 0.4.5.7 enables a remote participant in the Tor directory protocol to overload a target machine's CPU resources, disrupting its normal functioning.

Affected Systems and Versions

All versions of Tor prior to 0.4.5.7 are affected by this vulnerability. Users are advised to update their Tor software to the latest patched version to mitigate the risk.

Exploitation Mechanism

By exploiting this vulnerability, an attacker can send specially crafted requests to the targeted Tor instance, triggering a CPU exhaustion attack and leading to service disruption.

Mitigation and Prevention

Effective measures to address and prevent the CVE-2021-28089 vulnerability.

Immediate Steps to Take

To mitigate the risk associated with CVE-2021-28089, users should update their Tor software to version 0.4.5.7 or higher. Additionally, network administrators should monitor CPU usage and implement rate-limiting mechanisms to detect and prevent such attacks.

Long-Term Security Practices

Implementing regular software updates, conducting security audits, and deploying intrusion detection systems can enhance the long-term security posture of Tor networks.

Patching and Updates

It is crucial for users to stay informed about security updates released by the Tor Project. Timely application of patches and software updates is essential to protect against known vulnerabilities and security threats.