CVE-2025-59713

Executive Summary

CVE-2025-59713 is a critical security vulnerability in Snipe-IT, an open-source asset management system, affecting versions prior to 8.1.18. The vulnerability stems from unsafe deserialization of user-supplied data, which can allow an unauthenticated attacker to execute arbitrary code or perform remote code execution (RCE) on the server. The CVSS score of 6.8 indicates a high severity, with the potential for significant impact on confidentiality, integrity, and availability. The EPSS score of 0.0% suggests low exploitation activity in the wild, but the lack of a public patch status and the nature of the vulnerability make it a high-priority target for threat actors.

Supply Chain & Package Security

Snipe-IT is a PHP-based application, commonly deployed via Composer or Docker. The vulnerability is introduced through the application's core code, not a third-party package. However, organizations using Snipe-IT should verify their deployment method and ensure they are not using outdated or unmaintained versions. The package is not distributed via NPM, PyPI, Go, or Ruby, so no specific package manager advisories apply.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) - The vulnerability can be exploited remotely over the network.
• Attack Complexity (AC): Low (L) - No special conditions or complex attack sequences are required.
• Privileges Required (PR): None (N) - No authentication is needed to exploit the vulnerability.
• User Interaction (UI): None (N) - The victim does not need to perform any action.
• Scope (S): Unchanged (U) - The impact is confined to the vulnerable component.
• Confidentiality (C): Low (L) - Limited information disclosure is possible.
• Integrity (I): Low (L) - Limited data modification is possible.
• Availability (A): Low (L) - Limited service disruption is possible.

Threat Level: High. The combination of network exploitability, low complexity, and no required privileges makes this a serious threat. While the EPSS score is low, the potential for automated exploitation (e.g., via botnets) is significant.

Deep Dive & Mechanics

Unsafe deserialization occurs when an application deserializes data from an untrusted source without proper validation. In PHP, this often involves the unserialize() function, which can instantiate arbitrary objects and trigger magic methods like __wakeup() or __destruct(). An attacker can craft a malicious serialized payload that, when deserialized, executes arbitrary PHP code.

In Snipe-IT, the vulnerability likely exists in a component that processes serialized data from user input, such as cookies, session data, or API parameters. The attacker can send a specially crafted request containing a serialized PHP object that exploits a gadget chain within the application's codebase or its dependencies. This can lead to remote code execution, data exfiltration, or full server compromise.

Vulnerable vs. Patched Code

The vulnerable code likely uses unserialize() on user-controlled input without sanitization. The patched version (8.1.18) replaces this with a safe alternative, such as json_decode() or implements input validation and object whitelisting.

Vulnerable Code (Example):

// Vulnerable: Directly unserializing user input
$data = unserialize($_POST['data']);

Patched Code (Example):

// Patched: Using JSON decode with validation
$data = json_decode($_POST['data'], true);
if (json_last_error() !== JSON_ERROR_NONE) {
    // Handle error
}

Exploitation & Lab Setup

Red Team

To exploit this vulnerability, an attacker would craft a malicious serialized PHP object. Below is a conceptual example using a known PHP gadget chain (e.g., Monolog or Guzzle). Note: This is for educational purposes only.

<?php
// Example gadget chain for PHP unserialize (conceptual)
class Evil {
    public $cmd = 'id';
    public function __wakeup() {
        system($this->cmd);
    }
}

$payload = serialize(new Evil());
echo urlencode($payload);
?>

The attacker would then send this payload to the vulnerable endpoint, e.g., via a POST request:

curl -X POST https://target.com/vulnerable-endpoint -d "data=O:4:\"Evil\":1:{s:3:\"cmd\";s:2:\"id\";}"

Blue Team

To detect exploitation attempts, monitor for unusual serialized data in HTTP requests. Use the following detection rules.

Indicators of Compromise (IOCs)

• Network: HTTP requests containing serialized PHP objects (e.g., O:, a:, s: patterns) in POST data, cookies, or headers.
• File System: Unexpected files in the web root (e.g., shell.php, backdoor.php).
• Process: Unusual child processes spawned by the web server (e.g., id, whoami, nc).
• Logs: PHP error logs showing unserialize() errors or unexpected class instantiation.

Detection Engineering

YARA Rule

rule CVE_2025_59713_Unsafe_Deserialization {
    meta:
        description = "Detects serialized PHP objects in HTTP requests targeting Snipe-IT"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-59713"
    strings:
        $serialized = /[Oa]:\d+:/
        $php_class = /O:\d+:"[A-Za-z0-9_]+":/
    condition:
        $serialized or $php_class
}

Sigma Rule

title: CVE-2025-59713 - Unsafe Deserialization in Snipe-IT
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests containing serialized PHP objects indicative of CVE-2025-59713 exploitation
author: Valters IT
date: 2025-04-01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'data='
        cs-uri-query|re: '(O|a):\d+:'
    condition: selection
falsepositives:
    - Legitimate use of serialized data in custom applications
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-59713 - Unsafe Deserialization Attempt"; flow:to_server; content:"POST"; http_method; content:"data="; http_client_body; pcre:"/(O|a):\d+:/"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate: Upgrade Snipe-IT to version 8.1.18 or later.
2. Workaround: If immediate upgrade is not possible, implement a Web Application Firewall (WAF) rule to block requests containing serialized PHP objects.
3. Code Review: Audit all uses of unserialize() in the codebase and replace with safe alternatives like json_decode().
4. Monitoring: Enable detailed logging for all HTTP requests and monitor for suspicious patterns.
5. Network Segmentation: Isolate the Snipe-IT server from critical internal networks to limit blast radius.

Valters IT
Securing Digital Frontiers