Out of Bounds Read Vulnerability in libssh2: Denial of Service Risk
Summary
DEBIAN-CVE-2019-3858: An out of bounds read flaw was discovered in libssh2 before 1.8.1 when a specially crafted SFTP packet is received from the server. Affects libssh2 versions < 1.8.0-2.1. Fixed in 1.8.0-2.1. How to fix ↓
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Background
libssh2 is a widely used library that provides an API for implementing SSH2 client and server functionality. It is utilized in various applications for secure data transmission over networks. The library supports SFTP, SCP, and other protocols, making it a critical component in many software solutions. However, prior to version 1.8.1, libssh2 was susceptible to an out of bounds read vulnerability that could be exploited through specially crafted SFTP packets.
Vulnerability Detail
An out of bounds read flaw was discovered in libssh2 before version 1.8.1. This vulnerability arises when a malicious actor sends a specially crafted SFTP packet to a client using the library. If the SSH server is compromised, the attacker may be able to exploit this flaw to cause a Denial of Service (DoS) or potentially read sensitive data from the client's memory. The vulnerability is significant as it can lead to unauthorized access to sensitive information and disrupt service availability.
How To Fix
Minimum fixed version
1.8.0-2.1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade libssh2Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary measure, if updating the package is not immediately feasible, consider restricting access to the SSH server or implementing network-level controls to limit exposure to potentially malicious SFTP packets.
Conclusion
The out of bounds read vulnerability in libssh2 poses a significant risk to applications utilizing this library. It is crucial for developers and system administrators to update to the patched version to safeguard against potential exploits. Utilizing tools like Vulert can help in monitoring and managing open-source vulnerabilities effectively.
See every vulnerability recorded for libssh2 →
FAQ
The vulnerability is an out of bounds read flaw that can be exploited through specially crafted SFTP packets, potentially leading to Denial of Service or unauthorized data access.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. By simply uploading your manifest file like package-lock.json, you can check for vulnerabilities without needing to access the code.
If exploited, this vulnerability can lead to Denial of Service, causing applications to crash or become unresponsive, and may also allow attackers to read sensitive information from memory.
Yes, you should upgrade to version 1.8.0-2.1 or later to mitigate the vulnerability.
Detailed information can be found in the Debian CVE database, specifically at the link provided in the vulnerability details.
References
Related vulnerabilities
Recent vulnerabilities recorded for libssh2.
