CVE-2021-41119 : Exploit Details and Defense Strategies
Learn about CVE-2021-41119 affecting wire-server, where older releases are vulnerable to denial of service attacks via hash collisions in JSON parsing. Find mitigation steps and impacted versions.
Wire-server is the system server for the wire back-end services. Releases prior to v2022-03-01 are subject to a denial of service attack via a crafted object causing a hash collision. This allows an attacker to disrupt the server's operations rendering it unresponsive.
Understanding CVE-2021-41119
This vulnerability in wire-server's JSON parser can lead to a denial of service affecting the server's performance.
What is CVE-2021-41119?
The CVE-2021-41119 vulnerability arises from a hash collision caused by a crafted object in wire-server releases before v2022-03-01, leading to potential denial of service due to increased server parsing time.
The Impact of CVE-2021-41119
The vulnerability has a medium severity base score of 5.3 according to CVSS v3.1. Attackers can exploit it remotely with low complexity, causing a denial of service for heavily used servers.
Technical Details of CVE-2021-41119
A closer look at the technical aspects of the vulnerability.
Vulnerability Description
The JSON parser issue allows attackers to trigger hash collisions, leading to denial of service by consuming excessive server parsing time.
Affected Systems and Versions
- Product: wire-server
- Vendor: wireapp
- Versions Affected: < v2022-03-01
Exploitation Mechanism
Attackers craft objects causing hash collisions in wire-server, slowing parsing speed and potentially crashing the server.
Mitigation and Prevention
Steps to secure systems and prevent exploitation.
Immediate Steps to Take
- Update wire-server to version 2022-03-01 or later to mitigate the vulnerability.
- Monitor server performance for any signs of denial of service attacks.
Long-Term Security Practices
- Regularly update wire-server and other software components to the latest versions.
- Implement network monitoring solutions to detect and mitigate denial of service attempts.
Patching and Updates
Ensure that on-premise instances of wire-server are promptly updated to version 2022-03-01 or higher to prevent denial of service attacks.