CVE-2011-2185 in Fabric
Summary
by MITRE
Fabric before 1.1.0 allows local users to overwrite arbitrary files via a symlink attack on (1) a /tmp/fab.*.tar file or (2) certain other files in the top level of /tmp/.
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Analysis
by VulDB Data Team • 11/15/2021
The vulnerability identified as CVE-2011-2185 affects the Fabric deployment framework version 1.1.0 and earlier, presenting a significant local privilege escalation risk through symbolic link attacks. This flaw resides in the temporary file handling mechanism of Fabric, specifically targeting the /tmp directory where temporary files are created during deployment operations. The vulnerability enables local attackers to manipulate the system by creating malicious symbolic links that redirect file operations to arbitrary locations, potentially allowing them to overwrite critical system files or inject malicious content into the deployment process.
The technical implementation of this vulnerability stems from Fabric's insecure temporary file creation practices within the /tmp directory. When Fabric executes deployment tasks, it generates temporary tar files with names following the pattern fab.*.tar in the /tmp directory. The flaw occurs because Fabric does not properly validate or secure these temporary files against symlink attacks, allowing attackers to create symbolic links with the same names before Fabric attempts to create the actual files. This race condition vulnerability falls under the category of insecure temporary file handling, which is classified as CWE-377 and CWE-378 within the Common Weakness Enumeration framework. The attack vector specifically targets the directory traversal and file overwrite capabilities that are commonly exploited in privilege escalation scenarios.
The operational impact of this vulnerability extends beyond simple file overwrites, as it can be leveraged to compromise the integrity of the entire deployment infrastructure. An attacker with local access can potentially overwrite configuration files, executable binaries, or system libraries that Fabric might reference during deployment operations. This creates a persistent backdoor opportunity where malicious code can be injected into the system through legitimate deployment processes. The vulnerability also demonstrates weaknesses in the principle of least privilege, as Fabric's temporary file handling does not adequately protect against local attackers who can manipulate the system's temporary file space. This flaw significantly undermines the security posture of systems using Fabric for automated deployments, particularly in environments where multiple users or processes interact with the system.
Mitigation strategies for CVE-2011-2185 should prioritize updating Fabric to version 1.1.0 or later, where the vulnerable temporary file handling has been addressed. System administrators should also implement additional protective measures such as restricting write permissions to the /tmp directory for non-privileged users, implementing proper file ownership controls, and monitoring for suspicious symlink creation patterns. The remediation aligns with ATT&CK technique T1059.001 for privilege escalation through file manipulation and T1078 for valid accounts exploitation. Organizations should also consider implementing automated security scanning tools that can detect insecure temporary file handling patterns and enforce proper file system permissions. Regular security audits of deployment frameworks and automation tools are essential to identify similar vulnerabilities that could be exploited through similar attack vectors, particularly focusing on race condition vulnerabilities and insecure temporary file creation practices that are commonly found in deployment and build automation tools.