The Research Unit of Qualys Threat (TRU) has revealed three workarounds in Ubuntu’s limitations for unprivileged users. Qualys verified that they reported these vulnerabilities responsibly to the Ubuntu Security Team in January 2025.
Qualys TRU found three different alternatives for these limitations, where each one allows local attackers to establish user spaces with complete administrative capabilities. These workarounds make it easier to exploit weaknesses in kernel elements that require significant administrative rights within a restricted setting. The constraints on unprivileged user namespaces were initially added in Ubuntu 23.10 and were activated by default in Ubuntu 24.04. It is crucial to mention that these alternatives alone do not lead to total system control; however, they pose a threat when paired with other vulnerabilities, particularly those related to the kernel.
The workarounds for security impact Ubuntu version 24.04 and later. Ubuntu 23.10 introduces inherent limitations for unprivileged user namespaces; nevertheless, they are not activated by default. These defenses were rolled out in this version, and users who previously activated and depended on them are impacted.
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