CVE-2024-42392
📋 TL;DR
This vulnerability in Cesanta Mongoose Web Server v7.14 allows attackers to trigger an infinite loop by sending input with unexpected characters. This can cause denial of service by consuming server resources. Anyone using the vulnerable version of Mongoose Web Server is affected.
💻 Affected Systems
- Cesanta Mongoose Web Server
📦 What is this software?
Mongoose by Cesanta
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service through resource exhaustion, potentially crashing the server and disrupting all hosted services.
Likely Case
Partial service degradation or temporary unavailability due to infinite loop consuming CPU cycles.
If Mitigated
Minimal impact with proper input validation and resource limits in place.
🎯 Exploit Status
Exploitation requires sending malformed input to the web server, which is typically accessible without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v7.15 or later
Vendor Advisory: https://github.com/cesanta/mongoose/releases
Restart Required: Yes
Instructions:
1. Download Mongoose v7.15 or later from GitHub. 2. Replace the vulnerable binary with the patched version. 3. Restart the Mongoose service.
🔧 Temporary Workarounds
Input Validation Filter
allImplement custom input validation to reject requests containing unexpected characters before they reach Mongoose.
# Configure reverse proxy (nginx example) to filter requests
location / {
if ($request_uri ~* "[^\x20-\x7E]") {
return 400;
}
proxy_pass http://mongoose_server;
}
Resource Limits
linuxSet CPU and memory limits on the Mongoose process to prevent complete resource exhaustion.
# Linux systemd example
[Service]
CPUQuota=80%
MemoryLimit=512M
🧯 If You Can't Patch
- Deploy a web application firewall (WAF) with rules to block malformed requests containing unexpected characters.
- Isolate the vulnerable server behind a reverse proxy that filters and sanitizes all incoming requests.
🔍 How to Verify
Check if Vulnerable:
Check the Mongoose version string in logs or via the server's status endpoint. If it shows version 7.14, it is vulnerable.Check Version:
mongoose --versionVerify Fix Applied:
Confirm the version is 7.15 or higher after patching. Test by sending controlled malformed requests and monitoring for infinite loops.📡 Detection & Monitoring
Log Indicators:
- Repeated identical requests from same source
- High CPU usage alerts
- Process restart logs
Network Indicators:
- Unusual patterns of malformed HTTP requests
- Increased traffic to specific endpoints
SIEM Query:
source="mongoose.log" AND ("error" OR "restart" OR "high cpu")