CVE-2019-13229 in deepin-clone
Summary
by MITRE
deepin-clone before 1.1.3 uses a fixed path /tmp/partclone.log in the Helper::getPartitionSizeInfo() function to write a log file as root, and follows symlinks there. An unprivileged user can prepare a symlink attack there to create or overwrite files in arbitrary file system locations. The content is not attacker controlled.
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Analysis
by VulDB Data Team • 10/17/2023
The vulnerability identified as CVE-2019-13229 affects deepin-clone versions prior to 1.1.3 and represents a privilege escalation flaw that leverages insecure temporary file handling within the Helper::getPartitionSizeInfo() function. This issue occurs when the application writes log information to a fixed path location at /tmp/partclone.log with root privileges, creating a predictable attack surface for unprivileged users. The vulnerability stems from the application's failure to properly validate or sanitize the temporary file path, allowing for symbolic link manipulation attacks that can result in arbitrary file creation or modification.
The technical implementation of this vulnerability involves the application's use of a hardcoded temporary file path without proper security checks. When the Helper::getPartitionSizeInfo() function executes, it creates or appends to /tmp/partclone.log with elevated privileges, but does not verify whether the target path is a symbolic link. An attacker can exploit this by creating a symbolic link at the expected location that points to a sensitive system file or directory, thereby gaining the ability to overwrite or create files in arbitrary locations with root permissions. This represents a classic symlink race condition vulnerability that falls under CWE-367.
From an operational perspective, this vulnerability allows unprivileged users to potentially compromise the integrity of the system by creating or modifying files with root privileges. The impact extends beyond simple file manipulation as it could enable attackers to modify critical system configuration files, create backdoor files, or overwrite binaries with malicious content. The attack requires the victim to have a running instance of deepin-clone with elevated privileges, making it a privilege escalation vulnerability rather than a direct remote code execution flaw. The vulnerability aligns with ATT&CK technique T1068 which covers privilege escalation through local exploitation of software vulnerabilities.
The mitigation strategy for this vulnerability involves updating deepin-clone to version 1.1.3 or later where the fixed implementation properly handles temporary file creation without using predictable paths or symbolic links. System administrators should also implement proper file system permissions and consider using more secure temporary file creation methods such as mkstemp() or similar functions that create files with restricted permissions and prevent symbolic link traversal. Additionally, monitoring for suspicious symbolic link creation in temporary directories can help detect potential exploitation attempts. Organizations should also consider implementing privilege separation techniques and ensuring that applications running with elevated privileges follow the principle of least privilege when handling temporary file operations.