Security Update for libssh2
Summary
DSA-3487-1: libssh2 - security update. Affects libssh2 versions < 1.4.2-1.1+deb7u2. Fixed in 1.4.2-1.1+deb7u2. How to fix ↓
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Background
libssh2 is a SSH2 client-side library that provides secure communication over a network. It is used by various applications to establish SSH sessions and transfer data securely. However, a vulnerability has been discovered in libssh2 that weakens the security of the SSHv2 handshake, potentially allowing an eavesdropper to decrypt or intercept SSH sessions.
Vulnerability Detail
The vulnerability in libssh2 arises from a flaw in the Diffie-Hellman negotiation process. During the handshake, libssh2 incorrectly passes the number of bytes instead of the number of bits to a function that expects the latter. This mistake significantly weakens the security of the handshake, making it easier for an attacker with sufficient resources to compromise the confidentiality and integrity of SSH sessions. This vulnerability is identified as CVE-2016-0787.
How To Fix
Minimum fixed version
1.4.2-1.1+deb7u2
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
There is no known workaround for this vulnerability. It is essential to apply the security update to ensure the integrity and confidentiality of SSH sessions.
Conclusion
The libssh2 library is vulnerable to a flaw in the Diffie-Hellman negotiation process, which weakens the security of SSHv2 handshakes. This could potentially allow an attacker to intercept or decrypt SSH sessions. To mitigate this risk, it is crucial to upgrade to the patched versions of libssh2 provided by Debian. For further assistance or support in addressing this vulnerability, please contact DevNack.com.
See every vulnerability recorded for libssh2 →
FAQ
libssh2 is a client-side library that enables secure communication over SSHv2 protocol. It is used by various applications to establish SSH connections and transfer data securely.
This vulnerability weakens the security of the SSHv2 handshake, potentially allowing an eavesdropper to decrypt or intercept SSH sessions. It is crucial to apply the security update to mitigate this risk.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability. Simply upload your manifest file (e.g., package-lock.json) and Vulert will analyze it for open-source vulnerabilities in real-time.
No, there are no known workarounds for this vulnerability. It is necessary to apply the security update to address the issue.
The updated libssh2 packages can be obtained from the official Debian repositories. For the oldstable distribution (wheezy), upgrade to version 1.4.2-1.1+deb7u2. For the stable distribution (jessie), upgrade to version 1.4.3-4.1+deb8u1.
Related vulnerabilities
Recent vulnerabilities recorded for libssh2.
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