CVE-2023-38737 Overview
IBM WebSphere Application Server Liberty versions 22.0.0.13 through 23.0.0.7 contains a denial of service vulnerability that allows remote attackers to exhaust server memory resources by sending specially-crafted requests. This vulnerability stems from improper input validation and resource management flaws, enabling attackers to cause service disruption without requiring authentication.
Critical Impact
Remote attackers can exploit this vulnerability to cause memory exhaustion on affected WebSphere Application Server Liberty instances, leading to service unavailability and potential business disruption.
Affected Products
- IBM WebSphere Application Server Liberty 22.0.0.13 through 23.0.0.7
- IBM WebSphere Application Server (Liberty profile)
Discovery Timeline
- 2023-08-16 - CVE-2023-38737 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2023-38737
Vulnerability Analysis
This vulnerability in IBM WebSphere Application Server Liberty enables denial of service attacks through memory resource exhaustion. The flaw is categorized under CWE-20 (Improper Input Validation) and CWE-400 (Uncontrolled Resource Consumption), indicating that the server fails to properly validate and limit incoming request data before allocating memory resources.
The vulnerability can be exploited remotely over the network without requiring any authentication or user interaction, making it accessible to any attacker who can reach the affected WebSphere Liberty server. The exploitation does not impact data confidentiality or integrity but causes complete availability loss through resource exhaustion.
IBM has tracked this vulnerability internally with X-Force ID 262567.
Root Cause
The root cause lies in improper input validation (CWE-20) combined with uncontrolled resource consumption (CWE-400). When processing certain malformed or specially-crafted HTTP requests, the WebSphere Application Server Liberty fails to implement adequate bounds checking on memory allocation. This allows an attacker to craft requests that cause the server to allocate excessive amounts of memory, eventually exhausting available resources and causing a denial of service condition.
Attack Vector
The attack is conducted remotely over the network by sending specially-crafted HTTP requests to the vulnerable WebSphere Application Server Liberty instance. The attacker does not require any privileges or authentication to exploit this vulnerability. By repeatedly sending malicious requests, an attacker can cause progressive memory consumption until the server becomes unresponsive or crashes.
The attack mechanism involves crafting requests that trigger the vulnerable code path where memory allocation is not properly bounded. This could involve manipulating request headers, body content, or other parameters that the server processes and stores in memory without adequate validation or limits.
Detection Methods for CVE-2023-38737
Indicators of Compromise
- Abnormal memory consumption patterns on WebSphere Application Server Liberty instances
- Server performance degradation or unresponsiveness without corresponding legitimate traffic increases
- JVM heap exhaustion warnings or OutOfMemoryError exceptions in server logs
- Unusual patterns of HTTP requests from single sources or with similar characteristics
Detection Strategies
- Monitor JVM memory metrics including heap usage, garbage collection frequency, and memory allocation rates
- Implement application performance monitoring (APM) to detect anomalous resource consumption patterns
- Configure log analysis for memory-related warnings and errors in WebSphere Liberty server logs
- Deploy network traffic analysis to identify unusual request patterns targeting WebSphere endpoints
Monitoring Recommendations
- Set up alerts for memory utilization thresholds exceeding normal operational baselines
- Monitor garbage collection activity for signs of memory pressure or exhaustion
- Track server response times as degradation may indicate resource exhaustion attacks in progress
- Review access logs for suspicious request patterns or high-volume traffic from individual sources
How to Mitigate CVE-2023-38737
Immediate Actions Required
- Identify all IBM WebSphere Application Server Liberty instances running versions 22.0.0.13 through 23.0.0.7
- Review the IBM Support Advisory #7027509 for detailed patch information
- Apply the security update to upgrade to WebSphere Application Server Liberty version 23.0.0.8 or later
- Implement network-level rate limiting to reduce exposure while patching is in progress
Patch Information
IBM has released a security fix addressing this vulnerability. Organizations should upgrade to IBM WebSphere Application Server Liberty version 23.0.0.8 or later. The official security advisory and patch details are available through IBM Support Page. Additional technical details can be found in the IBM X-Force Exchange.
Workarounds
- Implement network-level request rate limiting to reduce the impact of potential exploitation attempts
- Configure Web Application Firewall (WAF) rules to filter potentially malicious requests
- Restrict network access to WebSphere Application Server Liberty instances using firewall rules
- Monitor and limit maximum request sizes and connection counts at the load balancer level
- Consider deploying reverse proxy configurations with request validation capabilities
# Example: Configure connection limits in server.xml
# Add httpEndpoint configuration with connection management
# Refer to IBM documentation for specific configuration parameters
# https://www.ibm.com/support/pages/node/7027509
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
