CVE-2011-3152 in Ubuntu Linux
Summary
by MITRE
DistUpgrade/DistUpgradeFetcherCore.py in Update Manager before 1:0.87.31.1, 1:0.134.x before 1:0.134.11.1, 1:0.142.x before 1:0.142.23.1, 1:0.150.x before 1:0.150.5.1, and 1:0.152.x before 1:0.152.25.5 on Ubuntu 8.04 through 11.10 does not verify the GPG signature before extracting an upgrade tarball, which allows man-in-the-middle attackers to (1) create or overwrite arbitrary files via a directory traversal attack using a crafted tar file, or (2) bypass authentication via a crafted meta-release file.
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Analysis
by VulDB Data Team • 05/12/2026
The vulnerability identified as CVE-2011-3152 represents a critical security flaw in Ubuntu's Update Manager component, specifically within the DistUpgrade/DistUpgradeFetcherCore.py module. This issue affects multiple versions of Ubuntu spanning from 8.04 through 11.10, creating a widespread impact across the Ubuntu ecosystem. The vulnerability stems from a fundamental failure in the upgrade process validation mechanism that undermines the integrity of the system update procedure.
The technical flaw manifests in the improper handling of GPG signature verification during the upgrade process. When Update Manager processes upgrade tarballs, it fails to validate the cryptographic signatures before extracting files from the archive. This omission creates a window of opportunity for attackers to manipulate the upgrade process through crafted malicious files. The vulnerability operates under CWE-22, which describes directory traversal attacks, and specifically targets the trust model of package verification mechanisms. The absence of GPG signature validation means that any attacker who can intercept network traffic or compromise the update server can inject malicious content into the upgrade process.
The operational impact of this vulnerability is severe and multifaceted, encompassing both local privilege escalation and authentication bypass capabilities. Attackers can exploit the vulnerability to create or overwrite arbitrary files on the target system through directory traversal techniques, potentially allowing them to install malicious software or modify critical system components. Additionally, the vulnerability enables attackers to bypass authentication mechanisms by crafting malicious meta-release files that can deceive the update manager into accepting compromised upgrade packages. This dual nature of the vulnerability makes it particularly dangerous as it can be leveraged for both persistent system compromise and privilege escalation attacks.
The attack vector for CVE-2011-3152 typically involves a man-in-the-middle position where an attacker intercepts upgrade traffic between the Ubuntu system and its package repositories. The vulnerability aligns with ATT&CK technique T1068, which covers local privilege escalation through exploitation of system vulnerabilities, and T1566, which encompasses social engineering and man-in-the-middle attacks. The affected versions of Ubuntu include several major releases, making this vulnerability particularly impactful across the Linux desktop and server landscape. Organizations using these vulnerable versions face significant risk of system compromise, as the attack can be executed without requiring elevated privileges or specialized knowledge of the target system's internals.
Mitigation strategies for CVE-2011-3152 focus primarily on updating the affected systems to patched versions of the Update Manager component. The recommended approach involves applying the security patches released by Canonical, which restore proper GPG signature verification before file extraction occurs. System administrators should also implement network monitoring to detect unusual upgrade traffic patterns and consider implementing additional security controls such as network segmentation and traffic inspection. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and highlights the risks associated with delayed patch management in enterprise environments. Organizations should also consider implementing automated patch management solutions to ensure timely deployment of security updates across their infrastructure.