CVE-2019-17563
📋 TL;DR
This CVE describes a session fixation vulnerability in Apache Tomcat's FORM authentication mechanism. An attacker could potentially hijack user sessions during a narrow timing window, though exploitation is considered impractical. Affected systems include Apache Tomcat versions 9.0.0.M1 to 9.0.29, 8.5.0 to 8.5.49, and 7.0.0 to 7.0.98.
💻 Affected Systems
- Apache Tomcat
📦 What is this software?
Agile Engineering Data Management by Oracle
Hyperion Infrastructure Technology by Oracle
View all CVEs affecting Hyperion Infrastructure Technology →
Leap by Opensuse
Tomcat by Apache
Tomcat by Apache
Tomcat by Apache
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
An attacker could hijack authenticated user sessions, potentially gaining unauthorized access to sensitive data or performing actions as the victim user.
Likely Case
Minimal impact due to the narrow exploitation window making successful attacks improbable in most real-world scenarios.
If Mitigated
No impact if proper session management controls are in place or if FORM authentication is not used.
🎯 Exploit Status
Exploitation requires precise timing during FORM authentication and is considered impractical by the vendor.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Tomcat 9.0.30, 8.5.50, 7.0.99
Vendor Advisory: https://lists.apache.org/thread.html/8b4c1db8300117b28a0f3f743c0b9e3f964687a690cdf9662a884bbd%40%3Cannounce.tomcat.apache.org%3E
Restart Required: Yes
Instructions:
1. Download patched version from Apache Tomcat website. 2. Stop Tomcat service. 3. Backup configuration files. 4. Replace Tomcat installation with patched version. 5. Restore configuration files. 6. Start Tomcat service.
🔧 Temporary Workarounds
Disable FORM Authentication
allSwitch to alternative authentication mechanisms like BASIC, DIGEST, or CLIENT-CERT authentication.
Modify web.xml to use different authentication method
🧯 If You Can't Patch
- Implement additional session validation controls in applications
- Monitor for unusual session activity patterns
🔍 How to Verify
Check if Vulnerable:
Check Tomcat version and verify if FORM authentication is configured in web.xmlCheck Version:
catalina.sh version (Linux) or catalina.bat version (Windows)Verify Fix Applied:
Verify Tomcat version is 9.0.30+, 8.5.50+, or 7.0.99+📡 Detection & Monitoring
Log Indicators:
- Multiple session creations for same user in rapid succession
- Unusual session ID patterns
Network Indicators:
- Multiple authentication requests from same source in short timeframe
SIEM Query:
source="tomcat" AND (event="SESSION_CREATED" OR event="AUTHENTICATION") | stats count by src_ip, user🔗 References
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00013.html
- https://lists.apache.org/thread.html/8b4c1db8300117b28a0f3f743c0b9e3f964687a690cdf9662a884bbd%40%3Cannounce.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r3bbb800a816d0a51eccc5a228c58736960a9fffafa581a225834d97d%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r48c1444845fe15a823e1374674bfc297d5008a5453788099ea14caf0%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r6ccee4e849bc77df0840c7f853f6bd09d426f6741247da2b7429d5d9%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r9136ff5b13e4f1941360b5a309efee2c114a14855578c3a2cbe5d19c%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/raba0fabaf4d56d4325ab2aca8814f0b30a237ab83d8106b115ee279a%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/reb9a66f176df29b9a832caa95ebd9ffa3284e8f4922ec4fa3ad8eb2e%40%3Cissues.cxf.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2020/01/msg00024.html
- https://lists.debian.org/debian-lts-announce/2020/05/msg00026.html
- https://seclists.org/bugtraq/2019/Dec/43
- https://security.gentoo.org/glsa/202003-43
- https://security.netapp.com/advisory/ntap-20200107-0001/
- https://usn.ubuntu.com/4251-1/
- https://www.debian.org/security/2019/dsa-4596
- https://www.debian.org/security/2020/dsa-4680
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- http://lists.opensuse.org/opensuse-security-announce/2020-01/msg00013.html
- https://lists.apache.org/thread.html/8b4c1db8300117b28a0f3f743c0b9e3f964687a690cdf9662a884bbd%40%3Cannounce.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r3bbb800a816d0a51eccc5a228c58736960a9fffafa581a225834d97d%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r48c1444845fe15a823e1374674bfc297d5008a5453788099ea14caf0%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r6ccee4e849bc77df0840c7f853f6bd09d426f6741247da2b7429d5d9%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/r9136ff5b13e4f1941360b5a309efee2c114a14855578c3a2cbe5d19c%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/raba0fabaf4d56d4325ab2aca8814f0b30a237ab83d8106b115ee279a%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/reb9a66f176df29b9a832caa95ebd9ffa3284e8f4922ec4fa3ad8eb2e%40%3Cissues.cxf.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2020/01/msg00024.html
- https://lists.debian.org/debian-lts-announce/2020/05/msg00026.html
- https://seclists.org/bugtraq/2019/Dec/43
- https://security.gentoo.org/glsa/202003-43
- https://security.netapp.com/advisory/ntap-20200107-0001/
- https://usn.ubuntu.com/4251-1/
- https://www.debian.org/security/2019/dsa-4596
- https://www.debian.org/security/2020/dsa-4680
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujan2021.html
- https://www.oracle.com/security-alerts/cpujul2020.html
