CVE-2012-3381 in sblim-sfcb
Summary
by MITRE
sfcb in sblim-sfcb places a zero-length directory name in the LD_LIBRARY_PATH, which allows local users to gain privileges via a Trojan horse shared library in the current working directory.
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Analysis
by VulDB Data Team • 04/20/2017
The vulnerability identified as CVE-2012-3381 affects the sblim-sfcb software implementation, specifically within the sfcb component that handles library path operations. This issue stems from a flawed handling of the LD_LIBRARY_PATH environment variable during the execution of system processes. The vulnerability creates a security risk by inserting a zero-length directory name into the library search path, which fundamentally alters how shared libraries are resolved during program execution. This flaw exists in the software configuration and initialization routines that manage dynamic library loading mechanisms.
The technical implementation of this vulnerability exploits the inherent behavior of Unix-like operating systems where the LD_LIBRARY_PATH environment variable controls the search order for shared libraries. When a zero-length directory name is inserted into this path, it effectively creates a reference to the current working directory as part of the library search sequence. This occurs because the empty directory component in the path resolves to the current directory, allowing any shared library placed in that location to be loaded before system libraries. The flaw represents a classic path traversal and privilege escalation vulnerability that leverages the operating system's library loading mechanism.
The operational impact of this vulnerability allows local attackers to execute arbitrary code with elevated privileges by placing a malicious shared library in the current working directory. This Trojan horse approach enables attackers to bypass normal security controls and execute code with the privileges of the process running sfcb. The vulnerability is particularly dangerous because it requires no special permissions to exploit, as the attacker only needs to have write access to the current working directory where the vulnerable process executes. This creates a significant risk in environments where multiple users share the same system or where processes may be executed from directories with loose permissions. The privilege escalation occurs because the system loads the attacker-controlled library instead of the legitimate system library, potentially allowing full system compromise.
Mitigation strategies for this vulnerability involve immediate patching of the sblim-sfcb software to correct the library path handling implementation. System administrators should ensure that all instances of the vulnerable software are updated to versions that properly sanitize the LD_LIBRARY_PATH environment variable and prevent insertion of empty directory components. Additionally, implementing proper directory permissions and access controls can reduce the attack surface, ensuring that only authorized users can write to directories where vulnerable processes execute. The vulnerability aligns with CWE-428, which describes "Security Features in Unusual Locations," and maps to ATT&CK technique T1068, "Exploitation for Privilege Escalation," through the exploitation of library loading mechanisms. Organizations should also consider implementing runtime monitoring and anomaly detection to identify potential exploitation attempts involving LD_LIBRARY_PATH manipulation.