OpenSSH Vulnerability: Progress Display Manipulation Risk
Summary
ALPINE-CVE-2019-6109: An issue was discovered in OpenSSH 7.9. Affects openssh versions < 7.9_p1-r3. Fixed in 7.9_p1-r3. How to fix ↓
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Background
OpenSSH is a widely used open-source implementation of the SSH (Secure Shell) protocol, which provides secure remote access to systems. It is known for its robust security features, including encrypted connections and secure file transfers. However, certain versions of OpenSSH are vulnerable to a specific issue that allows malicious actors to manipulate client output during file transfers, potentially leading to security breaches.
Vulnerability Detail
An issue was discovered in OpenSSH 7.9 due to missing character encoding in the progress display. A malicious server or a Man-in-the-Middle attacker can exploit this vulnerability by employing crafted object names, using ANSI control codes to manipulate the client output. This can lead to scenarios where additional files being transferred are hidden from the user, creating a significant security risk. The vulnerability is identified as CVE-2019-6109 and has a CVSS score of 6.8, indicating a moderate level of severity.
How To Fix
Minimum fixed version
7.9_p1-r3
This is the first release that contains the fix.
sudo apk add --upgrade opensshTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can avoid connecting to untrusted servers or ensure that they are using secure connections with verified hosts. Additionally, monitoring network traffic for unusual activity can help mitigate risks until the patch is applied.
Conclusion
The OpenSSH vulnerability CVE-2019-6109 poses a risk to users by allowing malicious actors to manipulate client output during file transfers. It is crucial to update to the patched version to mitigate this risk. Users are encouraged to monitor their systems and apply the necessary updates promptly.
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FAQ
CVE-2019-6109 is a vulnerability in OpenSSH that allows attackers to manipulate client output during file transfers due to missing character encoding in the progress display.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without requiring any signup.
The potential risks include unauthorized manipulation of file transfer outputs, which can lead to data breaches or loss of sensitive information.
Yes, the patched version of OpenSSH is 7.9_p1-r3 for Alpine Linux. Updating to this version will resolve the vulnerability.
If immediate updates are not possible, consider implementing temporary workarounds such as avoiding connections to untrusted servers and monitoring network traffic.
References
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