CVE-2025-41432

Executive Summary

CVE-2025-41432 is a local out-of-bounds write vulnerability affecting OpenHarmony v5.1.0 and prior versions. This flaw allows a local attacker to achieve arbitrary code execution within the context of pre-installed applications. The vulnerability is classified as a memory corruption issue (CWE-787) and carries a CVSS score of 5.5 (Medium). Exploitation is restricted to scenarios where the attacker already has local access to the device, limiting the attack surface but still posing a significant risk to device integrity and data confidentiality. No public proof-of-concept or exploit code is currently available, and the patch status remains unknown.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Local (L) – The attacker must have physical or shell access to the device.
• Attack Complexity (AC): Low (L) – No special conditions are required beyond local access.
• Privileges Required (PR): Low (L) – The attacker needs some level of user privileges.
• User Interaction (UI): None (N) – No victim interaction is needed.
• Scope (S): Unchanged (U) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – Potential full disclosure of sensitive data.
• Integrity (I): High (H) – Arbitrary code execution can modify system state.
• Availability (A): High (H) – Code execution can lead to denial of service.

Threat Level: Medium. The requirement for local access reduces the likelihood of widespread exploitation, but the impact on confidentiality, integrity, and availability is severe.

Deep Dive & Mechanics

The vulnerability resides in the memory management of pre-installed applications within OpenHarmony. An out-of-bounds write occurs when a local attacker provides crafted input that exceeds the allocated buffer size. This can corrupt adjacent memory regions, leading to arbitrary code execution.

Root Cause: Insufficient bounds checking in a system service or library used by pre-installed apps. The exact component is not disclosed, but the flaw is triggered by a local process sending a malicious IPC message or file.

Attack Flow:

1. Attacker gains local access (e.g., via ADB or a malicious app).
2. Attacker sends a specially crafted request to a vulnerable service.
3. The service writes data beyond the allocated buffer, overwriting function pointers or return addresses.
4. Control flow is hijacked, executing attacker-supplied shellcode.

Vulnerable vs. Patched Code

Since no patch is available, a hypothetical vulnerable code snippet is provided:

Vulnerable Code (C):

void process_data(char *input, size_t len) {
    char buffer[256];
    // No bounds check
    memcpy(buffer, input, len);
}

Patched Code (C):

void process_data(char *input, size_t len) {
    char buffer[256];
    if (len > sizeof(buffer)) {
        // Handle error
        return;
    }
    memcpy(buffer, input, len);
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• OpenHarmony device or emulator (v5.1.0 or earlier).
• Local shell access (e.g., via ADB).

Exploitation Steps:

1. Identify the vulnerable service (e.g., via fuzzing or static analysis).
2. Craft a payload that triggers an out-of-bounds write.
3. Use a technique like ROP (Return-Oriented Programming) to bypass mitigations (ASLR, NX).
4. Execute the payload to gain code execution within the pre-installed app context.

Example Payload (Python):

import socket

# Hypothetical vulnerable service on port 8080
sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
sock.connect("/data/local/tmp/vuln_service")

# Craft oversized input
payload = b"A" * 512
sock.send(payload)
sock.close()

Blue Team

Detection:

• Monitor for abnormal IPC messages or file operations from low-privileged processes.
• Use memory integrity checks (e.g., CFG, shadow stacks) to detect control flow hijacking.

Mitigation:

• Apply strict input validation and bounds checking in all system services.
• Enable Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP).
• Restrict local access via ADB and enforce least privilege.

Indicators of Compromise (IOCs)

• File Hashes: (None available)
• Network Signatures: (None available)
• Process Anomalies: Unexpected crashes in pre-installed apps (e.g., com.ohos.photos).
• Memory Artifacts: Corrupted heap or stack regions in system service memory dumps.

Detection Engineering

YARA Rule

rule CVE_2025_41432_Exploit {
    meta:
        description = "Detects potential exploit attempts for CVE-2025-41432"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $s1 = "memcpy" ascii wide nocase
        $s2 = "buffer" ascii wide nocase
        $s3 = "out-of-bounds" ascii wide nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2025-41432 Exploit Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects abnormal IPC messages targeting vulnerable OpenHarmony services
author: Valters IT
logsource:
    product: linux
    service: syslog
detection:
    selection:
        - "out-of-bounds write"
        - "buffer overflow"
    condition: selection
falsepositives:
    - Legitimate debugging tools
level: high

Suricata Rule

alert ip any any -> any any (msg:"CVE-2025-41432 Exploit Attempt"; content:"|41 41 41 41|"; offset:0; depth:512; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

• Immediate: Restrict local access to trusted users only. Disable ADB debugging on production devices.
• Long-term: Apply vendor patch when released. Implement robust input validation and bounds checking in all system services.
• Workaround: Use application sandboxing to limit the impact of code execution within pre-installed apps.

Valters IT
DevSecOps & Cyber Threat Intelligence