CVE-2019-9677 – This CVE describes a buffer overflow vulnerabil... (How to Fix)

Q: What is the severity of CVE-2019-9677?

CVE-2019-9677 has a CVSS score of 9.8 (CRITICAL). This CVE describes a buffer overflow vulnerability in the CGI interface of certain Dahua IP cameras. Attackers can exploit it by sending specially crafted packets to execute arbitrary code or crash devices. Affected are specific Dahua camera models with firmware versions built before August 18, 2019.

📋 TL;DR

This CVE describes a buffer overflow vulnerability in the CGI interface of certain Dahua IP cameras. Attackers can exploit it by sending specially crafted packets to execute arbitrary code or crash devices. Affected are specific Dahua camera models with firmware versions built before August 18, 2019.

💻 Affected Systems

Products:

IPC-HDW1X2X
IPC-HFW1X2X
IPC-HDW2X2X
IPC-HFW2X2X
IPC-HDW4X2X
IPC-HFW4X2X
IPC-HDBW4X2X
IPC-HDW5X2X
IPC-HFW5X2X

Versions: Firmware versions with Build time before August 18, 2019

Operating Systems: Embedded Linux

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects specific Dahua camera models listed; other models or firmware built after August 18, 2019 are not vulnerable.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Remote code execution leading to complete device compromise, lateral movement to internal networks, and persistent backdoor installation.

🟠

Likely Case

Device crash/reboot causing service disruption, or limited code execution for reconnaissance and credential harvesting.

🟢

If Mitigated

Denial of service from crash attempts, but no code execution due to network segmentation and exploit mitigations.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Exploitation requires network access to the CGI interface; no authentication needed. Public exploit code exists.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Firmware with Build time on or after August 18, 2019

Vendor Advisory: https://www.dahuasecurity.com/support/cybersecurity/details/637

Restart Required: Yes

Instructions:

1. Identify affected camera models and current firmware version. 2. Download updated firmware from Dahua support site. 3. Upload firmware via web interface or Dahua tools. 4. Reboot camera after update.

🔧 Temporary Workarounds

Network Segmentation

all

Isolate cameras on separate VLANs with strict firewall rules to block external CGI access.

Access Control Lists

all

Implement IP-based restrictions to allow only trusted management systems to access camera interfaces.

🧯 If You Can't Patch

Disable or block access to the CGI interface via firewall rules if not required for functionality.
Monitor network traffic for anomalous packets targeting camera IPs and CGI endpoints.

🔍 How to Verify

Check if Vulnerable:

Check firmware Build time via web interface: System > Information > Version; if Build time is before August 18, 2019, device is vulnerable.

Check Version:

Use Dahua tools or web interface; no universal CLI command available.

Verify Fix Applied:

Confirm Build time is August 18, 2019 or later after firmware update.

📡 Detection & Monitoring

Log Indicators:

Unusual CGI request patterns in camera logs
Device reboot/crash logs without clear cause

Network Indicators:

Malformed HTTP packets to camera CGI endpoints
Traffic spikes to camera management ports

SIEM Query:

source_ip="camera_ip" AND (uri="*.cgi" OR user_agent="exploit")

📊 Metadata

CVE ID: CVE-2019-9677

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-120

Published: September 18, 2019

Last Updated: November 21, 2024

🔗 References

https://www.dahuasecurity.com/support/cybersecurity/details/637 Patch,Vendor Advisory
https://www.dahuasecurity.com/support/cybersecurity/details/637 Patch,Vendor Advisory

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