CVE-2023-51075
📋 TL;DR
CVE-2023-51075 is an infinite loop vulnerability in hutool-core's StrSplitter.splitByRegex function that allows attackers to cause Denial of Service (DoS) by manipulating input parameters. This affects any application using vulnerable versions of the hutool Java utility library. The vulnerability can be exploited remotely without authentication.
💻 Affected Systems
- hutool-core
📦 What is this software?
Hutool by Hutool
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability due to infinite loop consuming 100% CPU resources, requiring manual process termination and service restart.
Likely Case
Partial service degradation or temporary unavailability affecting specific endpoints that use the vulnerable function.
If Mitigated
Minimal impact with proper input validation, rate limiting, and monitoring in place to detect and block malicious requests.
🎯 Exploit Status
The vulnerability is simple to exploit by providing specially crafted regex patterns and input strings that trigger infinite loops.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v5.8.24 or later
Vendor Advisory: https://github.com/dromara/hutool/issues/3421
Restart Required: Yes
Instructions:
1. Update hutool-core dependency to v5.8.24+ in your project's pom.xml or build.gradle. 2. Rebuild and redeploy your application. 3. Restart affected services.
🔧 Temporary Workarounds
Input Validation Workaround
allImplement strict input validation to reject or sanitize regex patterns and input strings before passing to StrSplitter.splitByRegex
Timeout Protection
allWrap calls to StrSplitter.splitByRegex with timeout mechanisms to prevent infinite loops from consuming resources indefinitely
🧯 If You Can't Patch
- Implement Web Application Firewall (WAF) rules to detect and block malicious regex patterns in requests
- Deploy rate limiting and request throttling to mitigate DoS impact
🔍 How to Verify
Check if Vulnerable:
Check your project's dependency management file (pom.xml, build.gradle) for hutool-core version 5.8.23 or earlierCheck Version:
For Maven: mvn dependency:tree | grep hutool-core; For Gradle: gradle dependencies | grep hutool-coreVerify Fix Applied:
Verify hutool-core version is 5.8.24 or later in your dependency management file and rebuilt application📡 Detection & Monitoring
Log Indicators:
- High CPU usage spikes
- Application threads stuck in processing loops
- Timeout errors for specific endpoints
Network Indicators:
- Unusually high request rates to endpoints using string splitting functionality
- Requests containing complex regex patterns
SIEM Query:
source="application_logs" AND ("CPU usage" > 90% OR "timeout" OR "infinite loop")