CVE-2021-27502 – CVE-2021-27502 is an integer overflow vulnerabi... (How to Fix)

Q: What is the severity of CVE-2021-27502?

CVE-2021-27502 has a CVSS score of 7.4 (HIGH). CVE-2021-27502 is an integer overflow vulnerability in Texas Instruments TI-RTOS when using HeapMem heap configuration. It allows attackers to trigger heap corruption through specially crafted malloc calls, potentially leading to arbitrary code execution. This affects embedded systems and IoT devices running TI-RTOS with default HeapMem configuration.

📋 TL;DR

CVE-2021-27502 is an integer overflow vulnerability in Texas Instruments TI-RTOS when using HeapMem heap configuration. It allows attackers to trigger heap corruption through specially crafted malloc calls, potentially leading to arbitrary code execution. This affects embedded systems and IoT devices running TI-RTOS with default HeapMem configuration.

💻 Affected Systems

Products:

Texas Instruments TI-RTOS

Versions: All versions prior to patched versions

Operating Systems: TI-RTOS (embedded RTOS)

Default Config Vulnerable: ⚠️ Yes

Notes: Only vulnerable when configured to use HeapMem heap (which is the default configuration)

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete device compromise, data exfiltration, or device becoming part of botnet

🟠

Likely Case

Denial of service through device crashes or instability, with potential for limited code execution in targeted attacks

🟢

If Mitigated

Denial of service only if proper memory protections are in place, but code execution may still be possible

🌐 Internet-Facing: MEDIUM - Many affected devices are IoT/embedded systems with internet connectivity, but exploitation requires specific conditions

🏢 Internal Only: LOW - Primarily affects specialized embedded systems rather than traditional IT infrastructure

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires ability to trigger malloc with extremely large values, which may require specific application conditions

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check TI-RTOS updates and patches from Texas Instruments

Vendor Advisory: https://www.ti.com/tool/TI-RTOS-MCU

Restart Required: Yes

Instructions:

1. Download latest TI-RTOS version from Texas Instruments website. 2. Replace vulnerable TI-RTOS libraries. 3. Recompile and redeploy applications. 4. Restart affected devices.

🔧 Temporary Workarounds

Switch to HeapBuf heap

all

Configure TI-RTOS to use HeapBuf instead of HeapMem heap to avoid the vulnerable code path

Modify TI-RTOS configuration to set HeapMem to false and HeapBuf to true

Input validation

all

Add bounds checking for malloc size parameters in application code

Implement size validation before calling malloc functions

🧯 If You Can't Patch

Implement network segmentation to isolate affected devices
Deploy intrusion detection systems to monitor for exploitation attempts

🔍 How to Verify

Check if Vulnerable:

Check TI-RTOS configuration for HeapMem heap usage and review application code for malloc calls with user-controlled size parameters

Check Version:

Check TI-RTOS build configuration and version information in device firmware

Verify Fix Applied:

Verify TI-RTOS version is updated and HeapMem configuration is disabled or patched

📡 Detection & Monitoring

Log Indicators:

Unexpected device reboots
Memory allocation failures
Heap corruption errors

Network Indicators:

Unusual network traffic from embedded devices
Protocol anomalies in device communications

SIEM Query:

Search for: device_type:"TI-RTOS" AND (event:"crash" OR event:"reboot" OR error:"heap")

📊 Metadata

CVE ID: CVE-2021-27502

CVSS v3 Score: 7.4 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-190

Published: November 21, 2023

Last Updated: November 21, 2024

🔗 References

https://www.cisa.gov/news-events/ics-advisories/icsa-21-119-04 Third Party Advisory,US Government Resource
https://www.ti.com/tool/TI-RTOS-MCU Product
https://www.cisa.gov/news-events/ics-advisories/icsa-21-119-04 Third Party Advisory,US Government Resource
https://www.ti.com/tool/TI-RTOS-MCU Product

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2021-27502, you might also want to check these: