CVE-2008-4553 in qemu
Summary
by MITRE
qemu-make-debian-root in qemu 0.9.1-5 on Debian GNU/Linux allows local users to overwrite arbitrary files via a symlink attack on temporary files and directories.
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Analysis
by VulDB Data Team • 08/02/2021
The vulnerability identified as CVE-2008-4553 affects the qemu-make-debian-root utility within QEMU version 0.9.1-5 on Debian GNU/Linux systems. This represents a classic symlink attack scenario where local users can exploit improper handling of temporary files and directories to overwrite arbitrary files on the system. The flaw stems from insufficient validation of temporary file creation processes, allowing attackers to manipulate the symbolic link structure before the utility creates its temporary resources.
The technical implementation of this vulnerability involves the qemu-make-debian-root script creating temporary files and directories without proper security checks. When the script operates with elevated privileges during the root filesystem creation process, a local attacker can establish symbolic links in the temporary directory path before the utility creates its own temporary resources. This race condition allows the attacker to control what files are actually written to disk, potentially overwriting critical system files or configuration data. The vulnerability operates at the file system level and demonstrates poor privilege separation in temporary file handling mechanisms.
From an operational impact perspective, this vulnerability poses significant security risks to systems running affected QEMU versions, particularly those where users might have access to the system but not necessarily administrative privileges. The ability to overwrite arbitrary files through a symlink attack can lead to privilege escalation scenarios, system compromise, or denial of service conditions. Attackers could target critical system files, configuration directories, or even binaries that are part of the system's core functionality. The vulnerability is particularly concerning in multi-user environments where untrusted users might have access to system resources.
The flaw aligns with CWE-377: Insecure Temporary Files and CWE-378: Poorly Secure Temporary Files, both of which address weaknesses in temporary file creation and management. From an ATT&CK framework perspective, this vulnerability maps to T1059.007: Command and Scripting Interpreter: PowerShell and T1068: Exploitation for Privilege Escalation, as it enables local users to escalate their privileges through file system manipulation. The vulnerability also relates to T1548.001: Abuse of Functionality: Valid Accounts and T1059.001: Command and Scripting Interpreter: PowerShell, as it leverages legitimate system utilities to achieve unauthorized file modifications.
Mitigation strategies for this vulnerability include updating to a patched version of QEMU where the temporary file handling has been corrected to use secure methods such as creating temporary files with proper permissions and using unique naming schemes. System administrators should ensure that the qemu-make-debian-root utility is not executed with unnecessary privileges and that temporary directories are properly secured with restrictive permissions. Additionally, implementing proper file system monitoring and access controls can help detect and prevent unauthorized symbolic link creation attempts. The most effective solution remains applying the vendor-provided security patches that address the race condition in temporary file creation processes.