CVE-2015-6566 in Collaboration Platform
Summary
by MITRE
zarafa-autorespond in Zarafa Collaboration Platform (ZCP) before 7.2.1 allows local users to gain privileges via a symlink attack on /tmp/zarafa-vacation-*.
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Analysis
by VulDB Data Team • 07/02/2022
The vulnerability identified as CVE-2015-6566 affects the Zarafa Collaboration Platform version 7.2.1 and earlier, specifically targeting the zarafa-autorespond component. This issue represents a classic symlink attack vulnerability that exploits improper temporary file handling within the application's privilege escalation mechanisms. The vulnerability occurs when the zarafa-autorespond utility creates temporary files in the /tmp directory without adequate security checks, making it susceptible to symbolic link manipulation by local users.
The technical flaw stems from the application's failure to properly validate or secure temporary file creation processes. When zarafa-autorespond executes, it generates temporary files with predictable names in the /tmp directory, specifically following the pattern /tmp/zarafa-vacation-*. Local attackers can exploit this by creating symbolic links with these exact names before the application attempts to create the temporary files. This symlink attack allows malicious users to manipulate the file system in ways that can result in privilege escalation, as the application will write data to the attacker-controlled symlink target rather than the intended temporary file location.
This vulnerability operates under the broader category of privilege escalation through insecure temporary file handling, which maps to CWE-377: Insecure Temporary File and CWE-378: Creation of Temporary File With Insecure Permissions. The operational impact of this vulnerability is significant as it enables local users to potentially execute arbitrary code with elevated privileges, depending on the permissions of the target files that the symlink points to. Attackers could leverage this to gain root access or escalate their privileges to those of the Zarafa service account, which typically runs with elevated system permissions.
The attack vector demonstrates a fundamental flaw in the application's security design where proper input validation and secure temporary file creation practices are not implemented. The vulnerability is particularly concerning because it requires no network access or remote exploitation capabilities, making it accessible through simple local system access. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, as it provides a method for local users to elevate their privileges within the system.
Mitigation strategies for this vulnerability include upgrading to Zarafa Collaboration Platform version 7.2.1 or later, where the issue has been addressed through proper temporary file handling mechanisms. System administrators should also implement proper file system permissions and monitoring for suspicious symlink creation patterns in temporary directories. The recommended approach involves ensuring that temporary files are created with proper permissions, using secure temporary file creation functions, and implementing proper validation of file paths before file operations. Additionally, regular security audits should verify that no other applications within the system exhibit similar insecure temporary file handling behaviors, as this represents a common class of vulnerabilities that can be exploited to gain unauthorized system access.