Critical Vulnerability in libvncserver: Access to Uninitialized Data
Summary
ALPINE-CVE-2018-7225: An issue was discovered in LibVNCServer through 0.9.11. Affects libvncserver versions < 0.9.11-r2. Fixed in 0.9.11-r2. How to fix ↓
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Background
libvncserver is an open-source library that enables the creation of VNC (Virtual Network Computing) servers. It allows users to remotely control graphical desktops over a network. The library is widely used in various applications due to its ease of integration and support for multiple platforms. However, it has been found to be vulnerable to a critical issue that can lead to unauthorized access to sensitive data.
Vulnerability Detail
An issue was discovered in libvncserver through version 0.9.11. The vulnerability arises from the function rfbProcessClientNormalMessage() in rfbserver.c, which fails to properly sanitize the msg.cct.length parameter. This oversight can lead to access to uninitialized and potentially sensitive data, as well as other impacts such as integer overflow, when specially crafted VNC packets are processed. The severity of this vulnerability is reflected in its CVSS score of 9.8, indicating a critical risk to affected systems.
How To Fix
Minimum fixed version
0.9.11-r2
This is the first release that contains the fix.
sudo apk add --upgrade libvncserverTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If immediate patching is not feasible, consider implementing network-level security measures such as firewalls to restrict access to the VNC server. Additionally, monitor incoming VNC packets for anomalies that may indicate exploitation attempts.
Conclusion
The vulnerability in libvncserver poses a significant risk due to its potential to expose sensitive data and allow for further exploitation. It is crucial to update to the patched versions as soon as possible to mitigate this risk. Additionally, employing workarounds can help protect systems until updates can be applied.
See every vulnerability recorded for libvncserver →
FAQ
The CVSS score of this vulnerability is 9.8, indicating a critical risk.
All versions of libvncserver up to 0.9.11 are affected by this vulnerability.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without any signup.
The vulnerability can lead to unauthorized access to sensitive data and may allow attackers to exploit other vulnerabilities through integer overflow.
Yes, you can implement network-level security measures such as firewalls to restrict access to the VNC server and monitor incoming packets for anomalies.
References
Related vulnerabilities
Recent vulnerabilities recorded for libvncserver.
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