Critical Buffer Overflow Vulnerability in GNU Screen Package
Summary
ALPINE-CVE-2020-9366: A buffer overflow was found in the way GNU Screen before 4.8.0 treated the special escape OSC 49. Affects screen versions < 4.6.2-r1. Fixed in 4.6.2-r1. How to fix ↓
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Background
GNU Screen is a terminal multiplexer that allows users to manage multiple terminal sessions from a single window. It is widely used for its ability to detach and reattach sessions, making it a valuable tool for remote work and server management. However, a critical vulnerability has been identified in versions prior to 4.8.0, which exposes users to potential memory corruption and crashes.
Vulnerability Detail
A buffer overflow was found in the way GNU Screen before version 4.8.0 treated the special escape OSC 49. This vulnerability can be exploited through specially crafted output or a specific program, leading to memory corruption, crashes, or potentially other unspecified impacts. The severity of this vulnerability is reflected in its CVSS score of 9.8, indicating a high risk to users.
How To Fix
Minimum fixed version
4.6.2-r1
This is the first release that contains the fix.
sudo apk add --upgrade screenTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can avoid using the special escape OSC 49 until they can update to a patched version. This may involve modifying scripts or configurations that utilize this escape sequence.
Conclusion
The buffer overflow vulnerability in GNU Screen poses a significant risk to users, with the potential for memory corruption and crashes. It is crucial for users to update to the patched version to mitigate these risks. Utilizing tools like Vulert can help in monitoring for such vulnerabilities in real-time.
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FAQ
A buffer overflow occurs when a program writes more data to a block of memory, or buffer, than it was allocated for. This can lead to memory corruption, crashes, or exploitation by attackers.
You can check your version of GNU Screen by running the command 'screen --version' in your terminal. If it is below 4.8.0, it is vulnerable.
Exploitation of this vulnerability can lead to crashes of the Screen application, memory corruption, and potentially allow attackers to execute arbitrary code.
Yes, tools like Vulert can monitor and alert you in real-time for open-source vulnerabilities in your software without requiring access to the code or installation.
Detailed information about this vulnerability can be found in the CVE database under CVE-2020-9366 and on the Alpine Linux security advisories.
References
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