CVE-2014-3127 in dpkg
Summary
by MITRE
dpkg 1.17.x before 1.17.9, 1.16.x before 1.16.14, and 1.15.x before 1.15.10 for Debian squeeze and wheezy supports "C-style encoded filenames" while the patch program does not, which introduces an interaction error that allows attackers to conduct directory traversal attacks and create files outside of the intended directories via a crafted package. NOTE: this vulnerability exists because of an incorrect fix for CVE-2014-0471.
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Analysis
by VulDB Data Team • 06/19/2021
The vulnerability identified as CVE-2014-3127 represents a critical directory traversal flaw in the dpkg package management system affecting Debian distributions. This issue specifically impacts dpkg versions 1.17.x prior to 1.17.9, 1.16.x prior to 1.16.14, and 1.15.x prior to 1.15.10, creating a significant security risk during package installation processes. The vulnerability stems from an inconsistency between dpkg's handling of C-style encoded filenames and the patch utility's interpretation of these same filenames, which creates a dangerous interaction that can be exploited by malicious actors. The root cause of this vulnerability lies in an incorrect remediation for CVE-2014-0471, where the previous fix introduced a new weakness rather than properly addressing the underlying issue. This flaw allows attackers to manipulate package installation procedures to create files in unintended directories, effectively bypassing normal file system access controls and directory boundaries. The technical implementation involves the use of C-style escape sequences within filenames that dpkg processes differently than the standard patch utility, creating a mismatch that enables attackers to craft malicious packages. When a vulnerable system processes such a package, the inconsistency between how filenames are interpreted by dpkg versus how they are handled by the patch program results in unexpected file creation behavior. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal attacks. From an operational perspective, this vulnerability poses a severe threat to Debian-based systems as it allows for arbitrary file creation outside of intended installation paths, potentially enabling privilege escalation, system compromise, or data manipulation. Attackers can exploit this flaw by creating specially crafted package files that contain C-style encoded filenames designed to traverse directory structures and place malicious files in sensitive system locations. The impact extends beyond simple file creation to potential privilege escalation scenarios where attackers might place executable files in system directories or overwrite critical configuration files. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically leveraging package management system weaknesses to gain elevated system access. Organizations running affected versions of dpkg should immediately implement mitigation strategies including updating to patched versions of dpkg, implementing strict package verification procedures, and monitoring for unauthorized package installations. The vulnerability highlights the importance of thorough testing when implementing security fixes, as the attempted remediation for CVE-2014-0471 inadvertently created a new attack vector that could be exploited by malicious actors. System administrators should also consider implementing additional security controls such as package integrity checking, restricted package installation permissions, and regular vulnerability assessments to prevent exploitation of this and similar weaknesses in package management systems.