CVE-2015-4594
📋 TL;DR
CVE-2015-4594 is a session fixation vulnerability in eClinicalWorks Population Health (CCMR) where the application fails to assign new session IDs during user authentication. This allows attackers to hijack user sessions by using pre-existing session IDs. Healthcare organizations using vulnerable versions of eClinicalWorks CCMR are affected.
💻 Affected Systems
- eClinicalWorks Population Health (CCMR)
📦 What is this software?
Population Health by Eclinicalworks
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of healthcare data including PHI, unauthorized access to patient records, and potential manipulation of population health data.
Likely Case
Unauthorized access to patient health information and administrative functions, leading to privacy violations and potential data theft.
If Mitigated
Limited impact with proper network segmentation, strong authentication controls, and session monitoring in place.
🎯 Exploit Status
Exploitation requires initial access to obtain a session ID, but once obtained, session hijacking is straightforward. Multiple exploit resources are publicly available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches released by eClinicalWorks in 2015
Vendor Advisory: Not publicly available - contact eClinicalWorks support
Restart Required: Yes
Instructions:
1. Contact eClinicalWorks support for the specific patch. 2. Apply the patch following vendor instructions. 3. Restart the CCMR application services. 4. Verify session management now generates new IDs on authentication.
🔧 Temporary Workarounds
Implement Web Application Firewall (WAF)
allDeploy WAF rules to detect and block session fixation attempts
Session Timeout Reduction
allReduce session timeout values to limit exposure window
Configure application session timeout to minimum practical value (e.g., 15-30 minutes)
🧯 If You Can't Patch
- Isolate the CCMR system in a segmented network with strict access controls
- Implement multi-factor authentication and monitor for unusual session activity
🔍 How to Verify
Check if Vulnerable:
Test authentication flow: 1. Capture session ID before login. 2. Authenticate. 3. Check if session ID changes. If same, vulnerable.Check Version:
Check application version through admin interface or contact eClinicalWorks supportVerify Fix Applied:
Repeat vulnerable check: session ID should change after successful authentication.📡 Detection & Monitoring
Log Indicators:
- Multiple logins with same session ID
- Session IDs persisting across authentication events
- Unusual session reuse patterns
Network Indicators:
- HTTP requests with manipulated session cookies
- Session fixation attack patterns in web traffic
SIEM Query:
source="ccmr_logs" AND (event="authentication" AND session_id NOT CHANGED) OR (session_id COUNT BY user > threshold)🔗 References
- http://packetstormsecurity.com/files/135533/eClinicalWorks-Population-Health-CCMR-SQL-Injection-CSRF-XSS.html
- http://www.securityfocus.com/archive/1/537420/100/0/threaded
- https://www.exploit-db.com/exploits/39402/
- http://packetstormsecurity.com/files/135533/eClinicalWorks-Population-Health-CCMR-SQL-Injection-CSRF-XSS.html
- http://www.securityfocus.com/archive/1/537420/100/0/threaded
- https://www.exploit-db.com/exploits/39402/
