CVE-2019-8955 : What You Need to Know
Learn about CVE-2019-8955, a vulnerability in Tor versions prior to 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x prior to 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, allowing remote denial of service attacks by causing memory exhaustion.
In versions prior to 0.3.3.12 of Tor, 0.3.4.x before 0.3.4.11, 0.3.5.x prior to 0.3.5.8, and 0.4.x before 0.4.0.2-alpha, a remote denial of service attack targeting Tor clients and relays is possible by causing memory exhaustion in the KIST cell scheduler.
Understanding CVE-2019-8955
This CVE identifies a vulnerability in Tor that could lead to a denial of service attack on Tor clients and relays.
What is CVE-2019-8955?
CVE-2019-8955 is a vulnerability in Tor versions prior to 0.3.3.12, 0.3.4.x before 0.3.4.11, 0.3.5.x prior to 0.3.5.8, and 0.4.x before 0.4.0.2-alpha. It allows attackers to exploit the KIST cell scheduler, causing memory exhaustion and potentially leading to a denial of service attack.
The Impact of CVE-2019-8955
This vulnerability could be exploited by remote attackers to target Tor clients and relays, potentially causing a denial of service by overwhelming the system with memory exhaustion.
Technical Details of CVE-2019-8955
CVE-2019-8955 involves the following technical aspects:
Vulnerability Description
The vulnerability in Tor versions allows for a remote denial of service attack by exploiting the KIST cell scheduler, leading to memory exhaustion.
Affected Systems and Versions
- Tor versions prior to 0.3.3.12
- Tor 0.3.4.x before 0.3.4.11
- Tor 0.3.5.x prior to 0.3.5.8
- Tor 0.4.x before 0.4.0.2-alpha
Exploitation Mechanism
Attackers can exploit this vulnerability by causing memory exhaustion in the KIST cell scheduler, impacting Tor clients and relays.
Mitigation and Prevention
To address CVE-2019-8955, consider the following mitigation strategies:
Immediate Steps to Take
- Update Tor to versions 0.3.3.12, 0.3.4.11, 0.3.5.8, or 0.4.0.2-alpha to mitigate the vulnerability.
- Monitor network traffic for any signs of exploitation.
Long-Term Security Practices
- Regularly update Tor and other software to patch known vulnerabilities.
- Implement network monitoring and intrusion detection systems to detect and prevent attacks.
Patching and Updates
- Apply patches provided by Tor to address the vulnerability.
- Stay informed about security advisories and updates from Tor to protect against potential threats.