CVE-2020-24217 – This vulnerability allows unauthenticated attac... (How to Fix)

Q: What is the severity of CVE-2020-24217?

CVE-2020-24217 has a CVSS score of 9.8 (CRITICAL). This vulnerability allows unauthenticated attackers to upload malicious firmware to HiSilicon-based video encoders, potentially leading to remote code execution. It affects IPTV/H.264/H.265 video encoders using the box application. Attackers can exploit this without any credentials.

📋 TL;DR

This vulnerability allows unauthenticated attackers to upload malicious firmware to HiSilicon-based video encoders, potentially leading to remote code execution. It affects IPTV/H.264/H.265 video encoders using the box application. Attackers can exploit this without any credentials.

💻 Affected Systems

Products:

HiSilicon-based IPTV/H.264/H.265 video encoders with box application

Versions: All versions prior to patched firmware (specific version unknown)

Operating Systems: Embedded Linux systems on HiSilicon hardware

Default Config Vulnerable: ⚠️ Yes

Notes: Affects devices with the vulnerable file-upload endpoint enabled, which appears to be default.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise allowing attackers to execute arbitrary code, install backdoors, disrupt video services, or pivot to internal networks.

🟠

Likely Case

Attackers upload malicious firmware to gain persistent access, disrupt video encoding services, or use devices for botnet activities.

🟢

If Mitigated

Unauthorized access attempts are blocked, but service availability might be impacted during attack attempts.

🌐 Internet-Facing: HIGH - Directly exploitable via HTTP without authentication, making internet-exposed devices immediate targets.

🏢 Internal Only: HIGH - Even internally, any network-accessible device can be compromised without credentials.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: CONFIRMED

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Multiple public exploit scripts and detailed technical analysis available. Attack requires only HTTP access to the device.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Unknown specific version - check with device manufacturer/vendor

Vendor Advisory: https://www.kb.cert.org/vuls/id/896979

Restart Required: Yes

Instructions:

1. Contact device manufacturer/vendor for patched firmware. 2. Backup current configuration. 3. Apply firmware update following vendor instructions. 4. Verify update applied successfully. 5. Restart device if required.

🔧 Temporary Workarounds

Network Access Control

linux

Restrict network access to video encoders using firewall rules

iptables -A INPUT -p tcp --dport 80 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

Disable Unnecessary Services

linux

Disable HTTP/file-upload services if not required for operation

systemctl stop httpd
systemctl disable httpd

🧯 If You Can't Patch

Isolate devices in separate VLAN with strict firewall rules allowing only necessary traffic
Implement network monitoring for unauthorized file upload attempts to the vulnerable endpoint

🔍 How to Verify

Check if Vulnerable:

Attempt unauthenticated HTTP POST to file-upload endpoint (typically /upload or similar) - if it accepts files without authentication, device is vulnerable.

Check Version:

Check device web interface or use vendor-specific CLI commands (varies by manufacturer)

Verify Fix Applied:

Test that file-upload endpoint now requires authentication or returns 403/401 for unauthenticated requests.

📡 Detection & Monitoring

Log Indicators:

Unauthenticated POST requests to file-upload endpoints
Unexpected firmware update activities
System log entries showing file uploads from unauthorized IPs

Network Indicators:

HTTP POST requests to /upload or similar endpoints without authentication headers
Unusual outbound connections from video encoders

SIEM Query:

source="video_encoder_logs" AND (http_method="POST" AND uri_path="/upload" AND NOT auth_success="true")

📊 Metadata

CVE ID: CVE-2020-24217

CVSS v3 Score: 9.8 (CRITICAL)

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

CWE: CWE-306

Published: October 6, 2020

Last Updated: November 21, 2024

🔗 References

http://packetstormsecurity.com/files/159597/HiSilicon-Video-Encoder-Command-Injection.html Exploit,Third Party Advisory,VDB Entry
http://packetstormsecurity.com/files/159599/HiSilicon-Video-Encoder-Malicious-Firmware-Code-Execution.html Exploit,Third Party Advisory,VDB Entry
https://kojenov.com/2020-09-15-hisilicon-encoder-vulnerabilities/ Exploit,Third Party Advisory
https://www.kb.cert.org/vuls/id/896979 Third Party Advisory,US Government Resource
http://packetstormsecurity.com/files/159597/HiSilicon-Video-Encoder-Command-Injection.html Exploit,Third Party Advisory,VDB Entry
http://packetstormsecurity.com/files/159599/HiSilicon-Video-Encoder-Malicious-Firmware-Code-Execution.html Exploit,Third Party Advisory,VDB Entry
https://kojenov.com/2020-09-15-hisilicon-encoder-vulnerabilities/ Exploit,Third Party Advisory
https://www.kb.cert.org/vuls/id/896979 Third Party Advisory,US Government Resource

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