CVE-2019-11542
📋 TL;DR
This vulnerability allows authenticated attackers with admin web interface access to execute arbitrary code via a stack buffer overflow in Pulse Secure VPN appliances. It affects Pulse Connect Secure and Pulse Policy Secure versions before specific patched releases. Attackers can potentially gain full control of affected VPN gateways.
💻 Affected Systems
- Pulse Connect Secure
- Pulse Policy Secure
📦 What is this software?
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
Pulse Policy Secure by Pulsesecure
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of VPN appliance leading to lateral movement into corporate networks, credential theft, and persistent backdoor access.
Likely Case
Privilege escalation to root/admin access on VPN appliance, enabling traffic interception, credential harvesting, and further network attacks.
If Mitigated
Limited to authenticated admin users only, reducing attack surface if proper access controls are implemented.
🎯 Exploit Status
Exploit chain documented in Black Hat presentations and security research blogs. Requires admin credentials but has been weaponized in real attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Pulse Connect Secure: 9.0R3.4, 8.3R7.1, 8.2R12.1, 8.1R15.1; Pulse Policy Secure: 9.0R3.2, 5.4R7.1, 5.3R12.1, 5.2R12.1, 5.1R15.1
Vendor Advisory: https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44101
Restart Required: Yes
Instructions:
1. Download appropriate patch from Pulse Secure support portal. 2. Backup current configuration. 3. Apply patch via admin interface. 4. Restart appliance. 5. Verify patch installation.
🔧 Temporary Workarounds
Restrict Admin Access
allLimit admin web interface access to trusted IP addresses only
Configure firewall rules to restrict access to admin interface (typically port 443) to specific management networks
Multi-Factor Authentication
allEnforce MFA for all admin accounts
Enable RADIUS or other MFA integration in Pulse Secure admin settings
🧯 If You Can't Patch
- Implement strict network segmentation to isolate VPN appliances from critical internal resources
- Enable detailed logging and monitoring for admin interface access and unusual activity
🔍 How to Verify
Check if Vulnerable:
Check current version via admin web interface > System > Maintenance > System InformationCheck Version:
ssh admin@vpn-appliance 'cat /etc/version' or check via web interfaceVerify Fix Applied:
Verify version number matches or exceeds patched versions listed in vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unusual admin login patterns
- Buffer overflow error messages in system logs
- Multiple failed admin login attempts followed by successful login
Network Indicators:
- Unusual outbound connections from VPN appliance
- Traffic patterns inconsistent with normal VPN usage
SIEM Query:
source="pulse-secure" AND (event_type="admin_login" AND result="success" AND src_ip NOT IN [trusted_admin_ips]) OR message="*buffer overflow*"🔗 References
- http://www.securityfocus.com/bid/108073
- https://devco.re/blog/2019/09/02/attacking-ssl-vpn-part-3-the-golden-Pulse-Secure-ssl-vpn-rce-chain-with-Twitter-as-case-study/
- https://i.blackhat.com/USA-19/Wednesday/us-19-Tsai-Infiltrating-Corporate-Intranet-Like-NSA.pdf
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44101
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2019-0010
- https://www.kb.cert.org/vuls/id/927237
- http://www.securityfocus.com/bid/108073
- https://devco.re/blog/2019/09/02/attacking-ssl-vpn-part-3-the-golden-Pulse-Secure-ssl-vpn-rce-chain-with-Twitter-as-case-study/
- https://i.blackhat.com/USA-19/Wednesday/us-19-Tsai-Infiltrating-Corporate-Intranet-Like-NSA.pdf
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44101
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2019-0010
- https://www.kb.cert.org/vuls/id/927237
