CVE-2016-8587 in Threat Discovery Appliance
Summary
by MITRE
dlp_policy_upload.cgi in Trend Micro Threat Discovery Appliance 2.6.1062r1 and earlier allows remote authenticated users to execute arbitrary code via an archive file containing a symlink to /eng_ptn_stores/prod/sensorSDK/data/ or /eng_ptn_stores/prod/sensorSDK/backup_pol/.
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Analysis
by VulDB Data Team • 12/02/2022
The vulnerability identified as CVE-2016-8587 resides within the Trend Micro Threat Discovery Appliance firmware version 2.6.1062r1 and earlier, representing a critical remote code execution flaw that can be exploited by authenticated attackers. This vulnerability specifically targets the dlp_policy_upload.cgi component which handles policy upload operations, creating a dangerous attack surface where malicious actors can leverage symbolic link manipulation to gain unauthorized system access. The flaw stems from insufficient validation of archive file contents during the upload process, allowing attackers to craft malicious archive files containing symbolic links that point to critical system directories. The affected paths include /eng_ptn_stores/prod/sensorSDK/data/ and /eng_ptn_stores/prod/sensorSDK/backup_pol/ which are crucial components of the appliance's data handling infrastructure.
The technical exploitation mechanism involves creating a specially crafted archive file that includes symbolic links referencing the vulnerable system directories. When the appliance processes this archive through the dlp_policy_upload.cgi script, the system follows the symbolic links and executes code within the targeted directories, effectively bypassing normal access controls and privilege boundaries. This represents a classic path traversal vulnerability that has been categorized under CWE-22, which deals with improper limitation of a pathname to a restricted directory. The vulnerability operates at the file system level, where the appliance's unpacking mechanism fails to properly sanitize symbolic link references, allowing attackers to manipulate the extraction process and execute arbitrary code with the privileges of the web server process.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with persistent access to the appliance's underlying system. Once exploited, attackers can modify or delete critical system files, install backdoors, or escalate privileges to gain full administrative control over the threat detection appliance. The appliance serves as a crucial network security component that monitors and analyzes network traffic for potential threats, making its compromise particularly dangerous as it could allow attackers to evade detection while gaining access to sensitive network data. This vulnerability directly impacts the integrity and availability of the security infrastructure, potentially allowing attackers to disable security features or manipulate threat detection capabilities. The attack requires only authenticated access to the appliance's web interface, which significantly lowers the attack threshold compared to other vulnerabilities that require additional reconnaissance or exploitation steps.
Organizations should implement immediate mitigations including firmware updates to versions that address this vulnerability, as well as network segmentation to limit access to the appliance to authorized personnel only. The principle of least privilege should be enforced by restricting user accounts to only necessary permissions and implementing multi-factor authentication for administrative access. Regular security assessments should include verification of the appliance's configuration to ensure that symbolic link handling is properly restricted. Additionally, monitoring for suspicious file upload activities and implementing intrusion detection systems that can identify anomalous behavior related to archive file processing will help detect potential exploitation attempts. This vulnerability aligns with ATT&CK technique T1059 which involves executing malicious code through legitimate system tools, and T1078 which covers valid accounts for persistence and privilege escalation. Organizations should also consider implementing application whitelisting controls to prevent execution of unauthorized code within the appliance's environment, and maintain regular backup procedures to ensure rapid recovery in case of successful exploitation.