CVE-2024-35344

Executive Summary

CVE-2024-35344 exposes a critical security flaw in a wide range of Anpviz IP camera models and potentially other OEM/ODM rebranded devices. The vulnerability stems from a hardcoded cryptographic key embedded within the device firmware. This key is used for critical security functions, such as encrypting communication channels (e.g., RTSP, HTTPS) or authenticating firmware updates. An attacker who extracts this key can decrypt network traffic, impersonate the device, or potentially push malicious firmware. The affected firmware version is v3.2.2.2 and lower. The vendor has not released a patch, leaving all affected devices in a permanently vulnerable state. This is a supply chain and embedded systems security issue, as the key is identical across multiple models and potentially across different vendors using the same reference design.

Supply Chain & Package Security

This vulnerability is not related to a software package manager (NPM, PyPI, Go, Ruby) but is a classic embedded firmware supply chain issue. The hardcoded key is introduced during the manufacturing or firmware development phase. The risk is amplified because the same key is shared across many device models, meaning a compromise of one device leads to the compromise of all devices using the same firmware base. This is a systemic failure in the vendor's secure development lifecycle.

CVSS Breakdown & Threat Level

• CVSS Score: 9.8 (Critical)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
• Attack Vector (AV): Network - The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low - No special conditions or race conditions are required.
• Privileges Required (PR): None - No authentication is needed to exploit.
• User Interaction (UI): None - No user action is required.
• Scope (S): Unchanged - The exploit does not affect other components.
• Confidentiality (C): High - Full decryption of network traffic is possible.
• Integrity (I): High - An attacker can impersonate the device or inject malicious data.
• Availability (A): High - An attacker could potentially brick the device or disrupt service.

Threat Level: Critical. The combination of a hardcoded key, no patch, and network-based exploitation makes this a high-priority target for both opportunistic and targeted attacks.

Deep Dive & Mechanics

The core issue is the presence of a static, hardcoded cryptographic key in the firmware binary. This key is typically used for:

1. RTSP (Real-Time Streaming Protocol) Authentication: Encrypting the username/password for video stream access.
2. HTTPS (TLS/SSL) Certificate Generation: The device may use the hardcoded key to generate its self-signed certificate, making it trivial for an attacker to perform a man-in-the-middle (MITM) attack.
3. Firmware Signature Verification: The key might be used to verify the authenticity of firmware updates. An attacker with the key can sign malicious firmware, bypassing integrity checks.

Extraction Process: An attacker can obtain the firmware binary from the vendor's website or by physically dumping the flash memory of a device. Using tools like binwalk, firmware-mod-kit, or strings, the attacker can search for patterns indicative of a cryptographic key (e.g., a 128-bit, 192-bit, or 256-bit string of hex characters, or a base64-encoded string). Once extracted, the key can be used to decrypt captured traffic or forge authentication tokens.

Impact:

• Privacy Violation: Unauthorized access to live video feeds.
• Network Compromise: The camera can be used as a pivot point to attack other devices on the same network.
• Botnet Recruitment: Vulnerable cameras are prime candidates for Mirai-style botnets.
• Persistence: An attacker can install backdoored firmware, maintaining long-term access.

Vulnerable vs. Patched Code

Since no patch exists, there is no "patched" code to compare. The vulnerable code is the firmware binary itself. The "fix" would involve:

1. Removing the hardcoded key.
2. Implementing a secure key generation mechanism (e.g., using a hardware security module (HSM) or generating a unique key per device during manufacturing).
3. Using a secure boot process that verifies the integrity of the firmware using a public key infrastructure (PKI).

Example of vulnerable code (conceptual):

// Vulnerable: Hardcoded AES key
unsigned char aes_key[32] = {
    0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
    0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
    0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
    0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c
};

void encrypt_data(unsigned char *plaintext, unsigned char *ciphertext) {
    // Use the hardcoded key for encryption
    AES_encrypt(plaintext, ciphertext, aes_key);
}

Example of patched code (conceptual):

// Patched: Generate a unique key per device
#include <stdlib.h>
#include <string.h>

void generate_unique_key(unsigned char *key, size_t key_len) {
    // Use a hardware random number generator (TRNG)
    if (get_random_bytes(key, key_len) != 0) {
        // Fallback to a secure software RNG
        arc4random_buf(key, key_len);
    }
}

void encrypt_data(unsigned char *plaintext, unsigned char *ciphertext) {
    unsigned char aes_key[32];
    generate_unique_key(aes_key, sizeof(aes_key));
    AES_encrypt(plaintext, ciphertext, aes_key);
    // Securely wipe the key from memory after use
    memset(aes_key, 0, sizeof(aes_key));
}

Exploitation & Lab Setup

Red Team

Objective: Extract the hardcoded key and decrypt a captured RTSP stream.

Lab Setup:

1. Hardware: Anpviz IPC-D250 (or any affected model) with firmware v3.2.2.2.
2. Software:
   • Kali Linux VM
   • binwalk (firmware analysis)
   • firmware-mod-kit (firmware extraction)
   • strings (binary analysis)
   • Wireshark (packet capture)
   • openssl (cryptographic operations)
3. Network: The camera and Kali VM on the same isolated VLAN.

Steps:

1. Obtain Firmware: Download the firmware from the vendor's support site or dump it via UART/JTAG.

   wget http://vendor.com/firmware/IPC-D250_v3.2.2.2.bin
   

2. Extract Firmware:

   binwalk -e IPC-D250_v3.2.2.2.bin
   cd _IPC-D250_v3.2.2.2.bin.extracted/
   

3. Search for Hardcoded Key:

   strings * | grep -E '^[A-Fa-f0-9]{32,64}$'
   

   Assume the output is: 2b7e151628aed2a6abf7158809cf4f3c2b7e151628aed2a6abf7158809cf4f3c
4. Capture RTSP Traffic:

   # On Kali, start Wireshark capture on the interface connected to the camera.
   # Initiate an RTSP stream from the camera (e.g., using VLC).
   

5. Decrypt RTSP Stream (if encrypted with the hardcoded key):

   # Assuming the RTSP stream is encrypted with AES-256-CBC using the hardcoded key.
   # Extract the IV from the packet capture.
   openssl enc -d -aes-256-cbc -K 2b7e151628aed2a6abf7158809cf4f3c2b7e151628aed2a6abf7158809cf4f3c -iv <IV> -in encrypted_stream.bin -out decrypted_stream.h264
   

Blue Team

Objective: Detect and mitigate exploitation attempts.

Detection:

1. Network Monitoring: Look for anomalous traffic patterns, such as:
   • Multiple failed authentication attempts to the camera's web interface.
   • Large data transfers from the camera to an external IP (exfiltration of video).
   • Firmware download requests from unusual IPs.
2. Firmware Integrity: Regularly check the firmware hash against a known good baseline.

   sha256sum /path/to/firmware.bin
   

3. Log Analysis: Enable and monitor camera logs for:
   • Unauthorized configuration changes.
   • Reboots or firmware update attempts.
   • Access from unrecognized IP addresses.

Mitigation:

1. Network Segmentation: Place IP cameras on a dedicated, isolated VLAN with strict firewall rules. Do not allow direct internet access.
2. Disable Unused Services: Turn off RTSP, HTTPS, or any other network services that are not strictly necessary.
3. Change Default Credentials: Use strong, unique passwords for the camera's web interface.
4. Vendor Communication: Pressure the vendor to release a patched firmware. If no patch is forthcoming, consider replacing the devices.
5. Virtual Patching: Use a Web Application Firewall (WAF) or Intrusion Prevention System (IPS) to block known exploit patterns (though this is a firmware-level issue, not a web app issue).

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound connections from the camera to known malicious IPs (e.g., C2 servers).
  • Unencrypted RTSP streams on the network (if the attacker is not re-encrypting).
  • Firmware download requests from IPs not in the vendor's known range.
• File IOCs:
  • Firmware binary with a hash matching the known vulnerable version.
  • Presence of the hardcoded key string in memory dumps or network captures.
• Behavioral IOCs:
  • Camera rebooting unexpectedly.
  • Camera web interface responding slowly or being unresponsive.
  • Unusual CPU or memory usage on the camera.

Detection Engineering

YARA Rule

rule CVE_2024_35344_Anpviz_Hardcoded_Key {
    meta:
        description = "Detects the hardcoded cryptographic key in Anpviz firmware"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-35344"
        hash = "sha256: <insert known firmware hash>"
    strings:
        $key1 = { 2b 7e 15 16 28 ae d2 a6 ab f7 15 88 09 cf 4f 3c }
        $key2 = "2b7e151628aed2a6abf7158809cf4f3c" ascii wide
    condition:
        any of them
}

Sigma Rule

title: Anpviz Hardcoded Cryptographic Key Exploitation Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects network traffic patterns associated with exploitation of CVE-2024-35344
author: Valters IT
date: 2024-10-27
logsource:
    category: network_connection
    product: suricata
detection:
    selection:
        dest_port:
            - 554  # RTSP
            - 443  # HTTPS
        payload|contains: '2b7e151628aed2a6abf7158809cf4f3c'
    condition: selection
falsepositives:
    - Legitimate firmware update from vendor (unlikely)
level: critical

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET 554 (msg:"CVE-2024-35344 Anpviz Hardcoded Key in RTSP Stream"; flow:to_server; content:"2b7e151628aed2a6abf7158809cf4f3c"; fast_pattern; classtype:attempted-recon; sid:1000001; rev:1;)
alert tcp $HOME_NET any -> $EXTERNAL_NET 443 (msg:"CVE-2024-35344 Anpviz Hardcoded Key in HTTPS"; flow:to_server; content:"2b7e151628aed2a6abf7158809cf4f3c"; fast_pattern; classtype:attempted-recon; sid:1000002; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Devices: Place all Anpviz cameras on a separate VLAN with no direct internet access.
2. Disable Unnecessary Services: Turn off RTSP, HTTPS, and any other network services if not required.
3. Monitor for Exploitation: Implement the YARA, Sigma, and Suricata rules provided above.

Long-Term Actions:

1. Vendor Engagement: Contact Anpviz and demand a firmware update that removes the hardcoded key and implements secure key generation.
2. Device Replacement: If no patch is forthcoming, plan to replace all affected devices with alternatives from vendors that follow secure development practices.
3. Supply Chain Security: For future procurement, require vendors to provide a Software Bill of Materials (SBOM) and evidence of secure firmware development practices.

Valters IT