CVE-2023-48230 : What You Need to Know
Learn about CVE-2023-48230, a vulnerability in Cap'n Proto that allows a remote peer to trigger a buffer underrun, potentially leading to a denial-of-service attack. Understand the impact, technical details, and mitigation steps.
Cap'n Proto WebSocket message can cause a crash due to a buffer underrun vulnerability. Learn about the impact, technical details, and mitigation steps for this CVE.
Understanding CVE-2023-48230
This CVE involves a vulnerability in Cap'n Proto that allows a remote peer to trigger a buffer underrun, potentially leading to a denial-of-service attack.
What is CVE-2023-48230?
Cap'n Proto, a data interchange format and RPC system, is affected by a buffer underrun vulnerability in versions 1.0 and 1.0.1. When using the KJ HTTP library with WebSocket compression enabled, a malicious peer can trigger a buffer underrun on a heap-allocated buffer.
The Impact of CVE-2023-48230
The buffer underrun results in a crash due to a constant 4-byte string being written out-of-bounds. While remote code execution is unlikely, it cannot be completely ruled out. This vulnerability allows for a remote denial-of-service attack.
Technical Details of CVE-2023-48230
This section covers the vulnerability description, affected systems and versions, and exploitation mechanism.
Vulnerability Description
The vulnerability arises when using the KJ HTTP library with WebSocket compression enabled in Cap'n Proto versions 1.0 and 1.0.1. The out-of-bounds write always contains a specific constant 4-byte string.
Affected Systems and Versions
Cap'n Proto versions >= 1.0 and < 1.0.1.1 are affected by this vulnerability. Previous versions of Cap'n Proto are not impacted.
Exploitation Mechanism
A malicious peer can exploit this vulnerability by causing a buffer underrun on a heap-allocated buffer when WebSocket compression is enabled via the KJ HTTP library.
Mitigation and Prevention
Protect your systems by following immediate steps and implementing long-term security practices to prevent such vulnerabilities.
Immediate Steps to Take
Ensure that WebSocket compression is disabled by default unless necessary. Update to Cap'n Proto version 1.0.1.1 to fix this vulnerability.
Long-Term Security Practices
Regularly update software components and libraries to the latest versions. Maintain least privilege access and implement stringent input validation practices.
Patching and Updates
Cap'n Proto 1.0.1.1 includes the necessary patch to address the buffer underrun vulnerability.