CVE-2025-1520
📋 TL;DR
This SQL injection vulnerability in PostHog's ClickHouse table functions allows authenticated attackers to execute arbitrary SQL commands, potentially leading to remote code execution. It affects PostHog installations where attackers have network access and valid credentials. The vulnerability stems from improper input validation in SQL query construction.
💻 Affected Systems
- PostHog
📦 What is this software?
Posthog by Posthog
⚠️ Risk & Real-World Impact
Worst Case
Full database compromise leading to data exfiltration, privilege escalation, and complete system takeover via RCE.
Likely Case
Database manipulation, data theft, and potential lateral movement within the network.
If Mitigated
Limited to authenticated user's permissions, potentially only data access within their scope.
🎯 Exploit Status
Authentication required, but SQL injection to RCE chain is documented in ZDI advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Commit 6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42 or later
Vendor Advisory: https://github.com/PostHog/posthog/commit/6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42
Restart Required: Yes
Instructions:
1. Update PostHog to version containing commit 6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42. 2. Restart PostHog services. 3. Verify the fix by checking version.
🔧 Temporary Workarounds
Network Segmentation
linuxRestrict network access to PostHog instances to only trusted IPs.
iptables -A INPUT -p tcp --dport [POSTHOG_PORT] -s [TRUSTED_IP] -j ACCEPT
iptables -A INPUT -p tcp --dport [POSTHOG_PORT] -j DROP
Authentication Hardening
allImplement strong authentication controls and limit user privileges.
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure to authenticated users only.
- Apply WAF rules to detect and block SQL injection patterns in requests.
🔍 How to Verify
Check if Vulnerable:
Check if PostHog version is before commit 6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42.Check Version:
Check PostHog version via web interface or API, or inspect git commit hash in deployment.Verify Fix Applied:
Confirm PostHog is running version with commit 6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42 or later.📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in PostHog/ClickHouse logs
- Multiple failed authentication attempts followed by SQL errors
Network Indicators:
- SQL injection patterns in HTTP requests to PostHog endpoints
SIEM Query:
source="posthog" AND ("sql" OR "injection" OR "CVE-2025-1520")