CVE-2020-23319
📋 TL;DR
CVE-2020-23319 is an assertion failure vulnerability in JerryScript's parser that could lead to denial of service or potentially arbitrary code execution. It affects systems running JerryScript 2.2.0, which is a lightweight JavaScript engine commonly embedded in IoT devices and resource-constrained environments. Attackers could trigger this vulnerability by providing specially crafted JavaScript input to the parser.
💻 Affected Systems
- JerryScript
📦 What is this software?
Jerryscript by Jerryscript
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise of affected devices
Likely Case
Denial of service causing application crashes or device instability
If Mitigated
Application restart required after crash with no data loss
🎯 Exploit Status
Proof of concept available in GitHub issue; exploitation requires ability to inject JavaScript into JerryScript parser
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.3.0 and later
Vendor Advisory: https://github.com/jerryscript-project/jerryscript/issues/3834
Restart Required: Yes
Instructions:
1. Upgrade JerryScript to version 2.3.0 or later. 2. Recompile any applications using JerryScript. 3. Restart affected services or devices.
🔧 Temporary Workarounds
Input validation and sanitization
allImplement strict input validation for JavaScript code processed by JerryScript
Process isolation
allRun JerryScript in isolated containers or sandboxes to limit impact of crashes
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable devices
- Deploy web application firewall rules to block suspicious JavaScript patterns
🔍 How to Verify
Check if Vulnerable:
Check JerryScript version: if version is exactly 2.2.0, system is vulnerableCheck Version:
jerry --version or check build configurationVerify Fix Applied:
Verify JerryScript version is 2.3.0 or later📡 Detection & Monitoring
Log Indicators:
- Application crashes with assertion failure messages
- JerryScript process termination
- Error logs containing 'parser_emit_cbc_backward_branch'
Network Indicators:
- Unusual JavaScript payloads sent to JerryScript endpoints
- Repeated connection attempts to JerryScript services
SIEM Query:
process_name:"jerry" AND (event_type:"crash" OR exit_code:139)