Critical Availability Vulnerability in libssh Package: CVE-2020-1730
Summary
ALPINE-CVE-2020-1730: A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. Affects libssh versions < 0.8.9-r0. Fixed in 0.8.9-r0. How to fix ↓
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Background
libssh is a C library that implements the SSH protocol, allowing secure communication over an unsecured network. It is widely used in various applications for secure remote access, file transfers, and other network services. The library supports multiple encryption algorithms and is designed to provide a robust framework for secure communications. However, certain versions of libssh are vulnerable to a flaw that can lead to system crashes under specific conditions, impacting availability.
Vulnerability Detail
A flaw was identified in libssh versions prior to 0.8.9 and 0.9.4, where the handling of AES-CTR (or DES ciphers if enabled) ciphers is inadequate. This vulnerability can cause the server or client to crash if the connection is not fully initialized and the system attempts to clean up the ciphers while closing the connection. The primary risk associated with this vulnerability is a denial of service, which can severely affect system availability and reliability.
How To Fix
Minimum fixed version
0.8.9-r0
This is the first release that contains the fix.
sudo apk add --upgrade libsshTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, you can limit the use of affected ciphers or implement additional monitoring to detect abnormal behavior in your application. However, the best course of action is to apply the patch as soon as possible.
Conclusion
CVE-2020-1730 represents a significant vulnerability in the libssh package that can compromise system availability. It is crucial for users of affected versions to apply the necessary updates to mitigate this risk. Regular monitoring and prompt updates are essential to maintain the security of your applications.
See every vulnerability recorded for libssh →
FAQ
CVE-2020-1730 is a vulnerability in the libssh package that can lead to system crashes due to improper handling of certain ciphers.
Versions of libssh prior to 0.8.9 for Alpine v3.10, 0.9.4 for Alpine v3.11, and 0.7.6-r3 for Alpine v3.9 are affected.
The vulnerability can lead to a denial of service, causing the server or client to crash and impacting system availability.
You can use Vulert, which monitors open-source vulnerabilities in your software using a manifest file like package-lock.json. Visit Vulert Scanner to check your application without signup.
The CVSS score for CVE-2020-1730 is 5.3, indicating a moderate level of risk.
References
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