CVE-2020-28984
📋 TL;DR
CVE-2020-28984 is a critical vulnerability in SPIP CMS that allows unauthenticated attackers to execute arbitrary code on affected systems. The vulnerability exists in the preferences configuration form due to insufficient parameter validation. All SPIP installations before version 3.2.8 are affected.
💻 Affected Systems
- SPIP CMS
📦 What is this software?
Spip by Spip
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and potential lateral movement within the network.
Likely Case
Remote code execution allowing attackers to deface websites, install malware, or establish persistent backdoors.
If Mitigated
Limited impact if proper network segmentation and web application firewalls are in place, though exploitation remains possible.
🎯 Exploit Status
The vulnerability is easily exploitable with publicly available proof-of-concept code. No authentication is required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.2.8 and later
Vendor Advisory: https://git.spip.net/spip/spip/commit/ae4267eba1022dabc12831ddb021c5d6e09040f8
Restart Required: No
Instructions:
1. Backup your SPIP installation and database. 2. Download SPIP 3.2.8 or later from the official repository. 3. Replace the affected file prive/formulaires/configurer_preferences.php with the patched version. 4. Verify the fix by checking the version.
🔧 Temporary Workarounds
Restrict access to admin interface
allLimit access to the SPIP administration interface to trusted IP addresses only
# Add to .htaccess or web server config
Order deny,allow
Deny from all
Allow from 192.168.1.0/24
Allow from 10.0.0.0/8
Disable affected form
linuxTemporarily disable or restrict access to the vulnerable preferences configuration form
# Rename or move the vulnerable file
mv prive/formulaires/configurer_preferences.php prive/formulaires/configurer_preferences.php.disabled
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to the SPIP administration interface
- Deploy a web application firewall (WAF) with rules to block exploitation attempts targeting this vulnerability
🔍 How to Verify
Check if Vulnerable:
Check if the file prive/formulaires/configurer_preferences.php exists and compare its content with the patched version from SPIP 3.2.8.Check Version:
Check the SPIP version in the administration panel or examine the ecrire/inc_version.php fileVerify Fix Applied:
Verify the SPIP version is 3.2.8 or later and that the vulnerable parameters (couleur, display, display_navigation, display_outils, imessage, spip_ecran) are properly validated in the preferences form.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to prive/formulaires/configurer_preferences.php with suspicious parameter values
- Multiple failed authentication attempts followed by successful exploitation
Network Indicators:
- HTTP requests containing malicious payloads in couleur, display, display_navigation, display_outils, imessage, or spip_ecran parameters
SIEM Query:
source="web_server" AND (url="*/prive/formulaires/configurer_preferences.php" AND (param="couleur" OR param="display" OR param="display_navigation" OR param="display_outils" OR param="imessage" OR param="spip_ecran"))🔗 References
- https://git.spip.net/spip/spip/commit/ae4267eba1022dabc12831ddb021c5d6e09040f8
- https://git.spip.net/spip/spip/compare/v3.2.7...v3.2.8
- https://lists.debian.org/debian-lts-announce/2020/12/msg00036.html
- https://www.debian.org/security/2020/dsa-4798
- https://git.spip.net/spip/spip/commit/ae4267eba1022dabc12831ddb021c5d6e09040f8
- https://git.spip.net/spip/spip/compare/v3.2.7...v3.2.8
- https://lists.debian.org/debian-lts-announce/2020/12/msg00036.html
- https://www.debian.org/security/2020/dsa-4798
