CVE-2025-63828
📋 TL;DR
A Host Header Injection vulnerability in Backdrop CMS 1.32.1 allows attackers to manipulate the Host header in password reset requests. This can redirect users to malicious domains and potentially enable session hijacking through cookie injection. All Backdrop CMS 1.32.1 installations are affected.
💻 Affected Systems
- Backdrop CMS
📦 What is this software?
Backdrop Cms by Backdropcms
⚠️ Risk & Real-World Impact
Worst Case
Attackers redirect users to malicious sites during password reset, steal session cookies, and gain unauthorized access to user accounts, potentially leading to account takeover and data theft.
Likely Case
Attackers redirect users to phishing sites during password reset flows, capturing credentials and potentially hijacking sessions if cookies are exposed.
If Mitigated
With proper input validation and secure headers, the impact is limited to failed redirect attempts with no data compromise.
🎯 Exploit Status
Public exploit code is available on GitHub, making exploitation straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch is available. Apply workarounds or upgrade to a future patched version when released.
🔧 Temporary Workarounds
Web Server Host Header Validation
allConfigure your web server (Apache/Nginx) to validate and restrict Host headers to prevent injection.
# Apache: Set UseCanonicalName On in httpd.conf
# Nginx: Set server_name directive with valid domains
Application-Level Input Sanitization
allModify Backdrop CMS code to sanitize and validate Host header values in password reset functionality.
# Edit backdrop/modules/user/user.module to add Host header validation
🧯 If You Can't Patch
- Implement a Web Application Firewall (WAF) with rules to block malicious Host header manipulation.
- Disable password reset functionality temporarily if not critical, or implement rate limiting on reset requests.
🔍 How to Verify
Check if Vulnerable:
Test by sending a password reset request with a manipulated Host header (e.g., using curl with -H 'Host: malicious.com') and check if redirects occur.Check Version:
Check Backdrop CMS version via admin interface or inspect core files for version info.Verify Fix Applied:
After applying workarounds, retest with manipulated Host headers; no redirects or injection should occur.📡 Detection & Monitoring
Log Indicators:
- Unusual Host header values in access logs (e.g., non-standard domains)
- Multiple failed password reset attempts from same IP
Network Indicators:
- HTTP requests with manipulated Host headers to password reset endpoints
- Redirects to external domains during reset flows
SIEM Query:
source="web_logs" AND (url="*/user/password" OR url="*/user/reset") AND (host_header!="expected_domain" OR host_header="*malicious*")