CVE-2018-25159: Epross AVCON6 OGNL Injection RCE Flaw

CVE-2018-25159 Overview

CVE-2018-25159 is a critical Object-Graph Navigation Language (OGNL) injection vulnerability affecting the Epross AVCON6 systems management platform. This vulnerability allows unauthenticated remote attackers to execute arbitrary commands on vulnerable systems by injecting malicious OGNL expressions through crafted HTTP requests. The vulnerability specifically targets the login.action endpoint, where attackers can exploit the redirect parameter to instantiate ProcessBuilder objects and execute system commands with root privileges.

Critical Impact

Unauthenticated remote attackers can achieve complete system compromise with root-level command execution through OGNL injection, potentially leading to full infrastructure takeover.

Affected Products

• Epross AVCON6 Systems Management Platform

Discovery Timeline

• 2026-03-11 - CVE-2018-25159 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2018-25159

Vulnerability Analysis

This OGNL injection vulnerability represents a severe code injection flaw in the Epross AVCON6 systems management platform. OGNL (Object-Graph Navigation Language) is an expression language used in Java-based frameworks, particularly Apache Struts, to access and manipulate object properties. When user-controlled input is passed directly to OGNL expression evaluators without proper sanitization, attackers can craft malicious expressions that execute arbitrary Java code on the server.

The vulnerability allows attackers to bypass authentication entirely and gain immediate command execution capabilities. The attack surface is particularly dangerous because it targets the login endpoint—a public-facing interface that cannot be easily restricted without breaking legitimate functionality.

Root Cause

The root cause of CVE-2018-25159 lies in insufficient input validation and improper handling of OGNL expressions within the login.action endpoint. The redirect parameter accepts user-supplied input that is subsequently processed by the OGNL expression evaluator without adequate sanitization. This allows attackers to inject OGNL expressions that instantiate Java objects and invoke methods, ultimately enabling arbitrary command execution. The vulnerability is classified under CWE-1334 (Unauthorized Actor), indicating that the system fails to properly authenticate or authorize requests before processing potentially dangerous operations.

Attack Vector

The attack is executed over the network without requiring any authentication or user interaction. Attackers craft HTTP requests to the login.action endpoint with malicious OGNL payloads embedded in the redirect parameter. These payloads leverage Java's ProcessBuilder class to spawn system processes with attacker-controlled commands.

A typical attack flow involves sending a POST request to the login endpoint with an OGNL expression that creates a ProcessBuilder instance, configures it with a malicious command string, and invokes the start() method to execute the command. Because the AVCON6 platform runs with elevated privileges, the executed commands inherit root-level access, providing attackers with complete control over the compromised system.

For detailed technical information and proof-of-concept details, refer to the Exploit-DB #47379 and VulnCheck Advisory.

Detection Methods for CVE-2018-25159

Indicators of Compromise

• HTTP POST requests to /login.action containing OGNL expression syntax such as ${, %{, #context, #cmd, or ProcessBuilder
• Unexpected child processes spawned by the AVCON6 Java application process
• Presence of web shells or unauthorized files in application directories
• Unusual outbound network connections from the AVCON6 server
• System log entries showing command execution originating from the web application context

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block OGNL injection patterns in request parameters
• Monitor HTTP access logs for requests to login.action with suspicious parameter values containing Java class references
• Implement endpoint detection rules to identify process creation chains where the AVCON6 Java process spawns shell commands
• Configure SIEM correlation rules to alert on authentication bypass attempts combined with subsequent privilege escalation indicators

Monitoring Recommendations

• Enable verbose logging on the AVCON6 application to capture all parameter values submitted to action endpoints
• Implement network traffic analysis to detect POST requests with abnormally large or encoded redirect parameter values
• Configure host-based intrusion detection to monitor for unexpected process execution patterns
• Establish baseline behavior for the AVCON6 application and alert on deviations such as unusual file system access or network connections

How to Mitigate CVE-2018-25159

Immediate Actions Required

• Isolate affected Epross AVCON6 systems from untrusted networks immediately
• Implement network-level access controls to restrict access to the management interface to trusted IP addresses only
• Deploy WAF rules specifically targeting OGNL injection patterns before any application updates
• Conduct forensic analysis to determine if exploitation has already occurred
• Review system logs and process execution history for signs of compromise

Patch Information

Organizations should consult with Epross directly regarding available security patches or firmware updates for the AVCON6 platform. Review the VulnCheck Advisory for the latest remediation guidance and vendor response information.

Workarounds

• Place the AVCON6 management interface behind a VPN or bastion host to prevent direct internet exposure
• Implement strict input validation at the reverse proxy level to reject requests containing OGNL metacharacters
• Configure network segmentation to limit lateral movement potential if the system is compromised
• Deploy application-layer filtering to sanitize or reject the redirect parameter in requests to login.action

# Example: Nginx WAF rule to block OGNL injection attempts
# Add to server configuration protecting AVCON6
location /login.action {
    if ($args ~* "(ProcessBuilder|Runtime|getRuntime|exec|%23|%24%7B)") {
        return 403;
    }
    proxy_pass http://avcon6_backend;
}