CVE-2023-34868
📋 TL;DR
CVE-2023-34868 is an assertion failure vulnerability in Jerryscript's parser that can cause denial of service through application crashes. It affects systems running Jerryscript 3.0 with the vulnerable commit. Attackers can trigger this by providing malicious JavaScript input to applications using Jerryscript.
💻 Affected Systems
- Jerryscript
📦 What is this software?
Jerryscript by Jerryscript
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service through application crash, potentially leading to service disruption and availability issues.
Likely Case
Application crash when processing specially crafted JavaScript input, causing temporary service interruption.
If Mitigated
Minimal impact if input validation and sandboxing prevent malicious JavaScript from reaching the parser.
🎯 Exploit Status
Exploitation requires ability to submit JavaScript to applications using Jerryscript. No public exploit code identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after commit 05dbbd1 with the fix applied
Vendor Advisory: https://github.com/jerryscript-project/jerryscript/issues/5083
Restart Required: Yes
Instructions:
1. Update Jerryscript to a version with the fix. 2. Rebuild applications using Jerryscript. 3. Restart affected services.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation to filter potentially malicious JavaScript before it reaches the parser.
Sandbox 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 monitoring and alerting for application crashes related to JavaScript processing.
🔍 How to Verify
Check if Vulnerable:
Check Jerryscript version and commit hash. If using commit 05dbbd1 or affected versions, system is vulnerable.Check Version:
Check build configuration or source code for Jerryscript version and commit information.Verify Fix Applied:
Verify Jerryscript has been updated to a version without the vulnerable commit and test with known safe JavaScript inputs.📡 Detection & Monitoring
Log Indicators:
- Application crashes during JavaScript parsing
- Assertion failure logs mentioning parser_parse_for_statement_start
Network Indicators:
- Unusual JavaScript payloads being submitted to applications
SIEM Query:
Search for application crash events containing 'jerryscript' or 'parser_parse_for_statement_start' in error messages.