CVE-2025-7216: Aidigu Deserialization RCE Vulnerability

CVE-2025-7216 Overview

A critical insecure deserialization vulnerability has been identified in lty628 Aidigu up to version 1.8.2. This vulnerability affects the checkUserCookie function within the /application/common.php file of the PHP Object Handler component. The flaw allows remote attackers to exploit improper handling of the rememberMe argument, leading to arbitrary object deserialization with potentially severe consequences for affected systems.

Critical Impact

Remote attackers can exploit this deserialization vulnerability to potentially execute arbitrary code, manipulate application logic, or compromise system integrity through crafted serialized payloads targeting the authentication cookie handling mechanism.

Affected Products

• lty628 Aidigu version 1.8.2 and earlier
• Systems utilizing the vulnerable PHP Object Handler component
• Applications implementing the affected checkUserCookie authentication mechanism

Discovery Timeline

• 2025-07-09 - CVE-2025-7216 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-7216

Vulnerability Analysis

This insecure deserialization vulnerability exists in the checkUserCookie function located in /application/common.php. The function processes the rememberMe cookie parameter without adequate validation or sanitization before deserializing its contents. PHP's native deserialization mechanism can be exploited when processing untrusted user input, allowing attackers to instantiate arbitrary objects and potentially trigger dangerous magic methods such as __wakeup(), __destruct(), or __toString().

When exploited, this vulnerability enables attackers to craft malicious serialized objects that, upon deserialization, can lead to remote code execution, file system manipulation, or other severe security impacts depending on the available classes within the application's codebase and autoloading configuration.

Root Cause

The root cause of CVE-2025-7216 is the direct deserialization of untrusted user input from the rememberMe cookie parameter without implementing proper input validation, type checking, or allowlist-based object instantiation controls. The checkUserCookie function fails to verify the integrity and authenticity of serialized data before processing, creating an exploitable attack surface for PHP object injection attacks.

Attack Vector

The attack can be initiated remotely over the network without requiring authentication. An attacker can craft a malicious serialized PHP object and inject it through the rememberMe cookie value. When the vulnerable checkUserCookie function processes this cookie during user session validation, the malicious payload is deserialized, potentially triggering a chain of method calls (known as a POP chain or Property Oriented Programming chain) that leads to arbitrary code execution or other malicious outcomes.

The exploit has been publicly disclosed, increasing the risk of active exploitation in the wild. Security researchers have documented the vulnerability through the HX Lab technical analysis which provides detailed information about the vulnerability mechanism.

Detection Methods for CVE-2025-7216

Indicators of Compromise

• Unusual or malformed values in rememberMe cookies containing PHP serialized object syntax (e.g., patterns starting with O:, a:, or s:)
• Web server logs showing requests with anomalously large cookie headers to authentication endpoints
• Unexpected PHP error messages related to object instantiation or class loading failures
• Evidence of unauthorized file creation, modification, or unexpected outbound network connections from the web server

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing serialized PHP object patterns in cookie values
• Deploy intrusion detection systems (IDS) with signatures targeting PHP deserialization attack patterns
• Monitor application logs for errors related to failed object deserialization or unexpected class instantiation
• Utilize endpoint detection and response (EDR) solutions to identify post-exploitation behaviors such as command execution or reverse shell connections

Monitoring Recommendations

• Enable detailed logging for the /application/common.php file and monitor for unusual activity patterns
• Configure real-time alerting on authentication-related endpoint anomalies
• Establish baseline metrics for cookie sizes and flag deviations that may indicate payload injection attempts
• Implement network monitoring for unexpected outbound connections from web application servers

How to Mitigate CVE-2025-7216

Immediate Actions Required

• Upgrade lty628 Aidigu to a patched version beyond 1.8.2 when available from the vendor
• Implement input validation to reject serialized PHP objects in cookie values
• Consider disabling the rememberMe functionality temporarily until a patch is applied
• Deploy WAF rules to block requests containing PHP serialization patterns in the rememberMe cookie

Patch Information

Organizations should monitor the official lty628 Aidigu repository and related security channels for patch releases addressing this vulnerability. Additional technical details and vulnerability tracking information are available through VulDB entry #315165. Until an official patch is released, implementing the workarounds and compensating controls described below is strongly recommended.

Workarounds

• Replace PHP's native unserialize() with safer alternatives such as json_decode() for cookie data processing
• Implement cryptographic signing (HMAC) for cookie values to detect tampering before processing
• Add strict allowlist validation for any objects that must be deserialized
• Consider implementing Content Security Policy (CSP) headers and other defense-in-depth measures

The following configuration example demonstrates a safer approach to cookie validation that avoids direct deserialization of untrusted input:

# Secure cookie validation configuration
# Instead of directly deserializing cookie data, use JSON encoding
# and implement HMAC signature verification

// Example: Validate cookie with HMAC before processing
$cookieData = $_COOKIE['rememberMe'] ?? '';
$parts = explode('.', $cookieData, 2);
if (count($parts) === 2) {
    $signature = $parts[0];
    $payload = $parts[1];
    $expectedSignature = hash_hmac('sha256', $payload, $secretKey);
    if (hash_equals($expectedSignature, $signature)) {
        $userData = json_decode(base64_decode($payload), true);
        // Process validated user data safely
    }
}