CVE-2009-0416 in sblim-sfcb
Summary
by MITRE
The SSL certificate setup program (genSslCert.sh) in Standards Based Linux Instrumentation for Manageability (SBLIM) sblim-sfcb 1.3.2 allows local users to overwrite arbitrary files via a symlink attack on the (1) /var/tmp/key.pem, (2) /var/tmp/cert.pem, and (3) /var/tmp/ssl.cnf temporary files.
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Analysis
by VulDB Data Team • 08/04/2021
The vulnerability identified as CVE-2009-0416 resides within the Standards Based Linux Instrumentation for Manageability (SBLIM) sblim-sfcb version 1.3.2 software suite, specifically within its SSL certificate generation script known as genSslCert.sh. This flaw represents a critical security weakness that enables local attackers to manipulate the certificate creation process through a carefully crafted symbolic link attack against temporary files used during SSL configuration. The affected system components include three specific temporary files located in the /var/tmp directory: key.pem, cert.pem, and ssl.cnf, which are essential for generating SSL certificates within the SBLIM framework. The vulnerability stems from the insecure handling of temporary files during the certificate generation process, where the script does not properly validate or secure the temporary file creation sequence.
The technical exploitation of this vulnerability occurs when a local attacker creates symbolic links with the same names as the temporary files that the genSslCert.sh script expects to create. When the script executes and attempts to write to these temporary files, it inadvertently writes to the attacker-controlled target files instead of the intended temporary locations. This type of attack falls under the category of time-of-check to time-of-use (TOCTOU) race conditions and represents a classic example of insecure temporary file handling as classified by CWE-377. The vulnerability demonstrates poor privilege management and inadequate file system security controls, allowing unauthorized file overwrites that could potentially lead to privilege escalation or data compromise within the system.
From an operational standpoint, this vulnerability poses significant risks to systems running SBLIM sblim-sfcb 1.3.2, particularly in enterprise environments where system management and monitoring capabilities are critical. The local privilege escalation potential means that any user with access to execute the genSslCert.sh script can potentially overwrite files with elevated privileges, depending on how the script is invoked. This attack vector aligns with ATT&CK technique T1068, which covers local privilege escalation through insecure file permissions and temporary file handling. The impact extends beyond simple file overwrites to potential system compromise, as attackers could overwrite critical system files, configuration data, or even executables that might be loaded by the system.
The mitigation strategies for this vulnerability include immediate patching of the sblim-sfcb software to version 1.3.3 or later, which addresses the insecure temporary file handling by implementing proper file validation and secure temporary file creation methods. System administrators should also implement additional security controls such as restricting write permissions to the /var/tmp directory and ensuring that temporary files are created with proper permissions that prevent symbolic link attacks. The solution should incorporate secure file creation practices that follow the principle of least privilege and utilize atomic file operations. Organizations should also conduct regular security audits of their system management tools to identify similar vulnerabilities in other components that might be susceptible to symlink-based attacks. This vulnerability serves as a reminder of the critical importance of secure temporary file handling in system management tools and the need for comprehensive security testing of automation scripts that operate with elevated privileges.