CVE-2019-25383
📋 TL;DR
This CVE describes multiple reflected cross-site scripting (XSS) vulnerabilities in Smoothwall Express's apcupsd.cgi script. Attackers can inject malicious JavaScript through various POST parameters, which executes in victims' browsers when they visit crafted URLs. Organizations running vulnerable Smoothwall Express versions are affected.
💻 Affected Systems
- Smoothwall Express
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator session cookies, perform actions as authenticated users, redirect to malicious sites, or install malware on administrator systems.
Likely Case
Session hijacking of Smoothwall administrators leading to unauthorized configuration changes, network compromise, or credential theft.
If Mitigated
Limited impact if proper input validation and output encoding are implemented, though XSS still poses session theft risks.
🎯 Exploit Status
Exploit code is publicly available on Exploit-DB (ID 46333), making exploitation straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://www.smoothwall.org
Restart Required: No
Instructions:
Check Smoothwall Express vendor site for updates. If no patch exists, implement workarounds or upgrade to a supported version.
🔧 Temporary Workarounds
Input Validation Filter
linuxImplement input validation to sanitize POST parameters in apcupsd.cgi script
Modify /usr/lib/smoothwall/apcupsd.cgi to validate/sanitize parameters like BATTLEVEL, RTMIN, etc.
Web Application Firewall
allDeploy WAF rules to block XSS payloads in POST requests to apcupsd.cgi
Configure WAF to filter malicious scripts in parameters
🧯 If You Can't Patch
- Restrict access to apcupsd.cgi script using firewall rules or authentication
- Disable UPS monitoring feature if not required
🔍 How to Verify
Check if Vulnerable:
Test by sending POST requests with script payloads to /cgi-bin/apcupsd.cgi and checking if scripts executeCheck Version:
cat /etc/smoothwall/versionVerify Fix Applied:
Verify input validation prevents script execution by testing with XSS payloads📡 Detection & Monitoring
Log Indicators:
- POST requests to apcupsd.cgi with script tags or JavaScript in parameters
- Unusual parameter values in web logs
Network Indicators:
- HTTP POST requests containing <script> tags or JavaScript functions in parameter values
SIEM Query:
source="web_logs" AND uri="/cgi-bin/apcupsd.cgi" AND (param="BATTLEVEL" OR param="RTMIN" OR param="BATTDELAY") AND (value CONTAINS "<script>" OR value CONTAINS "javascript:")