CVE-2022-26871: Trend Micro Apex Central RCE Vulnerability

CVE-2022-26871 Overview

An arbitrary file upload vulnerability exists in Trend Micro Apex Central that could allow an unauthenticated remote attacker to upload an arbitrary file which could lead to remote code execution. This critical vulnerability enables attackers to bypass authentication mechanisms and upload malicious files to vulnerable systems, potentially resulting in complete system compromise.

Critical Impact

This vulnerability is actively exploited in the wild and has been added to CISA's Known Exploited Vulnerabilities (KEV) catalog. Unauthenticated remote attackers can achieve remote code execution by exploiting the arbitrary file upload flaw, leading to complete system takeover.

Affected Products

• Trend Micro Apex Central 2019
• Trend Micro Apex One (SaaS)

Discovery Timeline

• 2022-03-29 - CVE-2022-26871 published to NVD
• 2025-12-22 - Last updated in NVD database

Technical Details for CVE-2022-26871

Vulnerability Analysis

This vulnerability is classified under CWE-345 (Insufficient Verification of Data Authenticity), indicating that the affected software fails to properly verify the authenticity or integrity of uploaded files. The arbitrary file upload vulnerability in Trend Micro Apex Central allows unauthenticated remote attackers to upload malicious files to the server. Due to insufficient validation of uploaded file content and type, an attacker can upload executable files, including web shells or other malicious payloads, which can then be executed on the server.

The vulnerability is particularly severe because it requires no authentication, no user interaction, and can be exploited remotely over the network. Successful exploitation grants attackers the ability to execute arbitrary code with the privileges of the Apex Central service, potentially leading to full system compromise, lateral movement within the network, and access to sensitive security management data.

Root Cause

The root cause of this vulnerability lies in the insufficient verification of data authenticity when processing file uploads. The application fails to properly validate the type, content, and destination of uploaded files, allowing attackers to bypass security controls. This lack of proper input validation and file type verification enables malicious files to be uploaded and subsequently executed on the server.

Attack Vector

The attack can be executed remotely over the network without requiring any form of authentication. An attacker can craft specially formatted HTTP requests to the vulnerable file upload endpoint in Trend Micro Apex Central. By manipulating file parameters and bypassing client-side restrictions, the attacker can upload malicious files such as web shells, scripts, or executable payloads to the server.

Once the malicious file is uploaded, the attacker can access or trigger the file to achieve remote code execution. This network-based attack vector, combined with the lack of authentication requirements and user interaction, makes this vulnerability highly exploitable in real-world scenarios.

Detection Methods for CVE-2022-26871

Indicators of Compromise

• Unexpected files appearing in Apex Central web directories, particularly files with executable extensions such as .aspx, .asp, .php, or .jsp
• Unusual HTTP POST requests to file upload endpoints with suspicious payloads or unexpected content types
• Web shell activity including command execution patterns, system reconnaissance commands, or data exfiltration attempts
• Anomalous process spawning from the Apex Central web service process

Detection Strategies

• Monitor web server logs for suspicious file upload requests targeting Apex Central endpoints, particularly those containing unusual file extensions or encoded payloads
• Implement file integrity monitoring (FIM) on Apex Central installation directories to detect unauthorized file creation or modification
• Deploy network-based intrusion detection signatures to identify exploitation attempts targeting CVE-2022-26871
• Review authentication logs for patterns indicating exploitation attempts from unauthenticated sources

Monitoring Recommendations

• Enable verbose logging on Trend Micro Apex Central and forward logs to a SIEM solution for centralized analysis
• Configure alerts for any new file creation within web-accessible directories of the Apex Central installation
• Monitor outbound network connections from the Apex Central server for signs of command and control communication
• Implement endpoint detection and response (EDR) solutions to detect post-exploitation activities such as lateral movement

How to Mitigate CVE-2022-26871

Immediate Actions Required

• Apply the security patch provided by Trend Micro immediately as this vulnerability is actively exploited
• If patching is not immediately possible, restrict network access to Apex Central management interfaces to trusted IP addresses only
• Conduct a thorough review of Apex Central servers for signs of compromise, including unexpected files and unauthorized access
• Implement network segmentation to isolate Apex Central servers from critical infrastructure

Patch Information

Trend Micro has released security patches to address this vulnerability. Organizations should apply the latest updates as described in the official security advisories. Refer to the Trend Micro Security Advisory and Trend Micro Support Solution for detailed patch information and installation instructions. Additional guidance is available from JPCERT Advisory and the CISA Known Exploited Vulnerabilities Catalog.

Workarounds

• Implement strict network access controls to limit access to Apex Central management interfaces to authorized administrators only
• Deploy a web application firewall (WAF) with rules to block suspicious file upload attempts and known exploitation patterns
• Disable or restrict file upload functionality if not required for business operations until patches can be applied
• Enable additional logging and monitoring on Apex Central servers to detect potential exploitation attempts

# Network restriction example - limit access to Apex Central management interface
# Add firewall rules to restrict access to trusted IP ranges only
# Windows Firewall example:
netsh advfirewall firewall add rule name="Block Apex Central External Access" dir=in protocol=tcp localport=443 action=block
netsh advfirewall firewall add rule name="Allow Apex Central Trusted IPs" dir=in protocol=tcp localport=443 remoteip=10.0.0.0/8 action=allow