CVE-2012-3378 in at-spi2-atk
Summary
by MITRE
The register_application function in atk-adaptor/bridge.c in GNOME at-spi2-atk 2.5.2 does not seed the random number generator and generates predictable temporary file names, which makes it easier for local users to create or truncate files via a symlink attack on a temporary socket file in /tmp/at-spi2.
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Analysis
by VulDB Data Team • 02/20/2019
The vulnerability identified as CVE-2012-3378 resides within the GNOME at-spi2-atk component version 2.5.2, specifically within the register_application function located in atk-adaptor/bridge.c. This flaw represents a significant security weakness that stems from improper random number generation practices within the application's temporary file creation mechanism. The vulnerability allows local attackers to exploit predictable temporary file names to perform symlink attacks against temporary socket files in the /tmp/at-spi2 directory, potentially enabling them to create or truncate arbitrary files with elevated privileges.
The technical root cause of this vulnerability lies in the register_application function's failure to properly seed the random number generator before generating temporary file names. This predictable behavior creates a scenario where an attacker can anticipate and manipulate the temporary file paths that the application will use. When the application creates temporary socket files in /tmp/at-spi2, the lack of proper randomization means that an attacker can pre-create symbolic links with the same names, effectively redirecting the application's file operations to unintended targets. This predictable naming scheme directly violates security best practices for temporary file handling and demonstrates a clear failure in the application's security design.
The operational impact of this vulnerability is substantial, as it enables local privilege escalation through symlink attacks that can result in arbitrary file creation or truncation. An attacker with local access to a system running the vulnerable GNOME at-spi2-atk component can exploit this weakness to overwrite critical system files, inject malicious code into running processes, or manipulate application behavior in ways that compromise system integrity. The vulnerability affects any local user who can execute code on the target system, making it particularly dangerous in multi-user environments where different users may have varying levels of access to the system. The attack vector is relatively straightforward, requiring only the ability to create symbolic links in the /tmp directory and wait for the vulnerable application to create its temporary socket files.
Security mitigations for this vulnerability should focus on ensuring proper random number seeding before temporary file creation and implementing robust temporary file handling practices. The most effective solution involves modifying the register_application function to properly seed the random number generator before generating temporary file names, thereby eliminating predictability in the file creation process. Additionally, implementing proper file permissions and using secure temporary file creation methods such as mkstemp or similar atomic operations can prevent symlink attacks from succeeding. Organizations should also consider implementing the principle of least privilege for applications running at-spi2-atk components and regularly audit temporary file usage patterns to detect potential exploitation attempts. This vulnerability aligns with CWE-330, which addresses insufficient entropy in random number generation, and can be categorized under ATT&CK technique T1059 for execution through local commands and T1068 for privilege escalation.