Source: security@trendmicro.com
An incorrect permissions assignment vulnerability in Trend Micro Deep Security 20.0 agents between versions 20.0.1-9400 and 20.0.1-23340 could allow a local attacker to escalate privileges on affected installations. Please note: an attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability.
Trend Micro Deep Security Agent versions 20.0.1-9400 to 20.0.1-23340 are vulnerable to a local privilege escalation due to an incorrect permissions assignment. An attacker with initial low-level access can leverage this flaw to gain elevated privileges, potentially leading to complete system compromise and data exfiltration.
Step 1: Initial Access: The attacker must first gain low-privileged access to the target system. This could be achieved through various means, such as exploiting another vulnerability, social engineering, or credential theft.
Step 2: Vulnerability Identification: The attacker identifies the vulnerable Deep Security Agent version.
Step 3: Permission Analysis: The attacker analyzes the file system permissions of the Deep Security Agent's files and directories to identify misconfigured permissions.
Step 4: Payload Creation: The attacker crafts a malicious payload, such as a modified binary, a malicious configuration file, or a malicious library, designed to execute with elevated privileges.
Step 5: Payload Injection: The attacker exploits the incorrect permissions to overwrite or replace a critical file within the Deep Security Agent's installation directory with the malicious payload.
Step 6: Triggering Execution: The attacker triggers the execution of the malicious payload. This could be achieved by restarting the Deep Security Agent service, waiting for a scheduled task, or triggering a specific agent function.
Step 7: Privilege Escalation: The malicious payload executes with the elevated privileges of the Deep Security Agent, granting the attacker higher-level access to the system.
The vulnerability stems from an incorrect configuration of file or directory permissions within the Deep Security Agent. Specifically, a component or service within the agent, likely related to its operational functionality (e.g., logging, update processes, or configuration management), is configured with overly permissive access controls. This allows a local, low-privileged user to modify or replace critical agent files, such as binaries, configuration files, or libraries. By manipulating these files, the attacker can inject malicious code that executes with the elevated privileges of the Deep Security Agent service, effectively achieving privilege escalation. The root cause is likely a failure to adhere to the principle of least privilege, where the agent component is granted more permissions than it strictly requires to perform its intended functions. This could be due to a coding error, a misconfiguration during the agent's installation or update process, or a design flaw in the agent's architecture.
While no specific APT groups are explicitly linked to this vulnerability at this time, any threat actor with the capability to gain initial access to a system could exploit this vulnerability. Given the widespread use of Deep Security, this vulnerability is likely to attract attention from various threat actors. CISA KEV status: Not yet listed, but likely to be added quickly once exploitation is observed.
Monitor file system activity for unexpected modifications to Deep Security Agent files and directories, especially those related to binaries, configuration files, and libraries.
Analyze process creation events for the Deep Security Agent service, looking for suspicious command-line arguments or parent processes.
Review system logs for errors or warnings related to the Deep Security Agent, particularly those indicating permission issues or file access failures.
Implement file integrity monitoring (FIM) to detect unauthorized changes to critical Deep Security Agent files.
Monitor network traffic for unusual activity originating from the Deep Security Agent, which could indicate command-and-control communication after a successful exploit.
Upgrade to the latest version of the Trend Micro Deep Security Agent that addresses this vulnerability. Refer to Trend Micro's security advisory for specific patch versions.
Implement the principle of least privilege by ensuring that the Deep Security Agent components have only the necessary permissions to perform their functions.
Review and harden file system permissions for the Deep Security Agent's installation directory and its subdirectories. Ensure that only authorized users and services have write access to critical files.
Regularly audit the Deep Security Agent's configuration and security settings to identify and address any potential vulnerabilities.
Implement a robust patch management process to ensure that security updates are applied promptly.
Consider using a host-based intrusion detection system (HIDS) to monitor for malicious activity on the system.
Implement network segmentation to limit the impact of a successful exploit.