CVE-2024-5580

Executive Summary

CVE-2024-5580 is a critical deserialization vulnerability in Allegra, a project management and help desk platform. The flaw resides in the loadFieldMatch method, where untrusted user-supplied data is deserialized without proper validation. An authenticated remote attacker can exploit this to execute arbitrary code in the context of the LOCAL SERVICE account, leading to full system compromise. With a CVSS score of 7.2 (High), this vulnerability poses a significant risk to affected deployments. No public proof-of-concept or patch is currently available, and the vendor has not released an advisory.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects the Allegra application directly, which is typically deployed as a standalone service.

CVSS Breakdown & Threat Level

• CVSS Score: 7.2 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (Authentication required)
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

The threat level is high due to the low complexity of exploitation and the potential for full system compromise. The requirement for authentication slightly reduces the attack surface but does not eliminate the risk.

Deep Dive & Mechanics

The vulnerability exists in the loadFieldMatch method of Allegra. This method is responsible for loading field matching configurations, likely used for data import or synchronization features. The flaw stems from the deserialization of untrusted data without proper validation or sanitization.

In Java-based applications (Allegra is built on Java), deserialization of untrusted data can lead to remote code execution if the application's classpath contains gadgets (classes that can be chained to execute arbitrary commands). An attacker can craft a malicious serialized object that, when deserialized, triggers a chain of method calls resulting in code execution.

The exploitation process typically involves:

1. Authenticating to the Allegra application.
2. Sending a crafted HTTP request to the vulnerable endpoint that triggers loadFieldMatch.
3. The malicious serialized payload is deserialized, leading to code execution in the context of the LOCAL SERVICE account.

The LOCAL SERVICE account has limited privileges but can still be leveraged to escalate privileges or move laterally within the network.

Vulnerable vs. Patched Code

Since no patch is available, a direct comparison is not possible. However, the vulnerable code likely resembles:

public void loadFieldMatch(HttpServletRequest request) {
    String data = request.getParameter("fieldMatchData");
    ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(data.getBytes()));
    Object obj = ois.readObject(); // Unsafe deserialization
    // Process obj...
}

A patched version would include validation and use of safe deserialization practices, such as:

public void loadFieldMatch(HttpServletRequest request) {
    String data = request.getParameter("fieldMatchData");
    // Validate data format and content
    if (!isValidFormat(data)) {
        throw new SecurityException("Invalid data");
    }
    // Use a whitelist of allowed classes
    ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(data.getBytes())) {
        @Override
        protected Class<?> resolveClass(ObjectStreamClass desc) throws IOException, ClassNotFoundException {
            if (!allowedClasses.contains(desc.getName())) {
                throw new InvalidClassException(desc.getName(), "Unauthorized deserialization");
            }
            return super.resolveClass(desc);
        }
    };
    Object obj = ois.readObject();
    // Process obj...
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• A valid authenticated session to Allegra.
• Knowledge of the vulnerable endpoint (likely /loadFieldMatch or similar).
• A Java deserialization payload generator (e.g., ysoserial).

Steps:

1. Identify the vulnerable endpoint by analyzing the application's API or source code.
2. Generate a malicious serialized payload using a gadget chain compatible with Allegra's classpath (e.g., CommonsCollections).
3. Send a POST request to the vulnerable endpoint with the payload in the fieldMatchData parameter.
4. The payload executes, spawning a reverse shell or executing arbitrary commands.

Example Request (using curl):

curl -X POST https://target.com/loadFieldMatch \
  -H "Cookie: JSESSIONID=valid_session_id" \
  -d "fieldMatchData=$(cat payload.ser)"

Payload Generation (using ysoserial):

java -jar ysoserial.jar CommonsCollections1 'cmd.exe /c powershell -e <base64_encoded_payload>' > payload.ser

Blue Team

Detection:

• Monitor for unusual deserialization activity in logs.
• Look for large or suspicious fieldMatchData parameters in HTTP requests.
• Use network monitoring to detect outbound connections from the Allegra service.

Prevention:

• Implement a Web Application Firewall (WAF) rule to block requests with suspicious fieldMatchData parameters.
• Apply the principle of least privilege to the LOCAL SERVICE account.
• Isolate Allegra in a segmented network.

Hunting:

• Search for Java deserialization gadget chains in the application's classpath.
• Review logs for java.io.InvalidClassException or similar errors.

Indicators of Compromise (IOCs)

• Network:
  • Outbound connections from the Allegra server to unknown IPs on common ports (e.g., 4444, 8080).
  • Unusual HTTP POST requests to /loadFieldMatch with large payloads.
• Host:
  • Unexpected processes spawned by the Allegra service (e.g., cmd.exe, powershell.exe).
  • New files created in the Allegra installation directory.
  • Modifications to system files or registry keys.
• Logs:
  • Java deserialization errors in application logs.
  • Authentication logs showing repeated access to the vulnerable endpoint.

Detection Engineering

YARA Rule

rule CVE_2024_5580_Deserialization {
    meta:
        description = "Detects malicious serialized Java objects targeting CVE-2024-5580"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-5580"
    strings:
        $magic = { AC ED 00 05 } // Java serialization magic bytes
        $class = "loadFieldMatch" nocase
        $gadget1 = "CommonsCollections" nocase
        $gadget2 = "Runtime" nocase
    condition:
        $magic at 0 and ($class or $gadget1 or $gadget2)
}

Sigma Rule

title: CVE-2024-5580 Allegra Deserialization RCE
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects exploitation attempts of CVE-2024-5580 via deserialization payloads
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: allegra
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'loadFieldMatch'
        cs-uri-query|length: '> 1000'
    condition: selection
falsepositives:
    - Legitimate large field match data
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2024-5580 Allegra Deserialization RCE"; flow:to_server,established; content:"POST"; http_method; content:"/loadFieldMatch"; http_uri; content:"fieldMatchData"; http_client_body; pcre:"/\\xac\\xed\\x00\\x05/"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the Allegra server from untrusted networks.
2. Restrict access to the vulnerable endpoint using a WAF or reverse proxy.
3. Monitor logs for signs of exploitation.

Long-term Fixes:

• Apply a vendor patch when available.
• Implement input validation and safe deserialization practices.
• Upgrade to a secure version of Allegra if released.
• Conduct a security audit of the application's codebase.

Workarounds:

• Disable the loadFieldMatch functionality if not required.
• Use a Java agent to monitor and block deserialization of untrusted data.

Valters IT
Securing Digital Frontiers