CVE-2020-23257
📋 TL;DR
A buffer overflow vulnerability in Espruino 2v05.41 allows attackers to trigger denial of service by exploiting the jsvGarbageCollectMarkUsed function. This affects systems running vulnerable versions of Espruino, an embedded JavaScript interpreter for microcontrollers.
💻 Affected Systems
- Espruino
📦 What is this software?
Espruino by Espruino
⚠️ Risk & Real-World Impact
Worst Case
Complete system crash or device reboot, potentially leading to permanent denial of service for affected embedded systems.
Likely Case
Application crash and service disruption requiring manual intervention to restore functionality.
If Mitigated
Limited impact with proper input validation and memory protection mechanisms in place.
🎯 Exploit Status
Exploitation requires crafting specific input to trigger the buffer overflow in garbage collection.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 2v05.41
Vendor Advisory: https://github.com/espruino/Espruino/issues/1820
Restart Required: Yes
Instructions:
1. Update Espruino to latest version. 2. Recompile firmware if using source. 3. Deploy updated firmware to affected devices.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation for JavaScript code processed by Espruino
Memory Protection
allEnable hardware memory protection features if supported by microcontroller
🧯 If You Can't Patch
- Isolate affected devices from untrusted networks
- Implement monitoring for abnormal memory usage patterns
🔍 How to Verify
Check if Vulnerable:
Check Espruino version with 'process.version' command or firmware versionCheck Version:
process.versionVerify Fix Applied:
Verify version is newer than 2v05.41 and test garbage collection functions📡 Detection & Monitoring
Log Indicators:
- Unexpected device reboots
- Memory allocation errors
- Garbage collection failures
Network Indicators:
- Unusual JavaScript payloads sent to embedded devices
SIEM Query:
device_logs: "Espruino" AND ("crash" OR "reboot" OR "memory error")