CVE-2020-23311
📋 TL;DR
CVE-2020-23311 is an assertion failure vulnerability in JerryScript's JavaScript parser that can cause denial of service through application crashes. Attackers can trigger this by providing specially crafted JavaScript input to applications using vulnerable JerryScript versions. This affects any system running applications that embed JerryScript 2.2.0 for JavaScript execution.
💻 Affected Systems
- JerryScript
📦 What is this software?
Jerryscript by Jerryscript
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if the assertion failure can be leveraged for memory corruption attacks.
Likely Case
Denial of service through application crashes when processing malicious JavaScript input.
If Mitigated
Limited impact with proper input validation and sandboxing of JavaScript execution environments.
🎯 Exploit Status
Proof of concept demonstrates triggering the assertion failure with specific JavaScript syntax. Exploitation requires ability to provide JavaScript input to vulnerable applications.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: JerryScript 2.3.0 and later
Vendor Advisory: https://github.com/jerryscript-project/jerryscript/issues/3822
Restart Required: Yes
Instructions:
1. Upgrade JerryScript to version 2.3.0 or later. 2. Rebuild any applications using JerryScript. 3. Restart affected services.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation to reject malformed JavaScript before processing by JerryScript.
Sandbox JavaScript Execution
allRun JerryScript in isolated containers or sandboxes to limit impact of crashes.
🧯 If You Can't Patch
- Implement network segmentation to isolate systems running vulnerable JerryScript versions
- Deploy web application firewalls to filter malicious JavaScript input patterns
🔍 How to Verify
Check if Vulnerable:
Check if applications use JerryScript version 2.2.0 by examining dependencies or running 'strings' on binaries for JerryScript version identifiers.Check Version:
Check application documentation or build configuration for JerryScript version, or use: grep -r 'jerry' /path/to/application/ | grep -i versionVerify Fix Applied:
Verify JerryScript version is 2.3.0 or later and test with known proof-of-concept inputs that previously caused crashes.📡 Detection & Monitoring
Log Indicators:
- Application crashes with JerryScript assertion failures
- Error messages containing 'js-parser-expr.c:3230' or 'parser_parse_object_initializer'
Network Indicators:
- Unusual JavaScript payloads in HTTP requests or other input channels
SIEM Query:
source="application.logs" AND ("assertion failed" OR "jerryscript" OR "js-parser-expr.c")