CVE-2025-25277

Executive Summary

CVE-2025-25277 is a type confusion vulnerability (CWE-843) affecting OpenHarmony versions up to and including 5.1.0. The flaw allows a local attacker to achieve arbitrary code execution within the context of pre-installed applications. The vulnerability is triggered by passing an incompatible type to a function or API, leading to memory corruption. While the CVSS score is 6.3 (Medium), the potential for local privilege escalation and code execution in a trusted application context makes it a significant threat in restricted scenarios, such as kiosk-mode devices or enterprise-managed OpenHarmony deployments. No public exploit code or proof-of-concept is currently available, and the patch status remains unknown.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Base Score: 6.3 (Medium)
• Attack Vector: Local (AV:L) – The attacker must have local access to the device.
• Attack Complexity: Low (AC:L) – No special conditions are required to exploit.
• Privileges Required: Low (PR:L) – The attacker needs basic user-level access.
• User Interaction: None (UI:N) – No user action is needed beyond the attacker's own actions.
• Scope: Unchanged (S:U) – The vulnerability does not cross security boundaries.
• Confidentiality Impact: High (C:H) – Full read access to sensitive data is possible.
• Integrity Impact: High (I:H) – Arbitrary code execution can modify system files.
• Availability Impact: High (A:H) – The attacker can crash or disrupt the system.

Threat Level: Medium. The local attack vector and requirement for pre-existing access reduce the immediate risk, but the high impact on confidentiality, integrity, and availability makes it a priority for patching in high-security environments.

Deep Dive & Mechanics

The vulnerability resides in the type handling logic of pre-installed applications within OpenHarmony. When a function or API expects a specific data type (e.g., a string, integer, or object), but receives an incompatible type (e.g., an array where a string is expected), the application fails to properly validate the input. This type confusion leads to memory corruption, which can be leveraged by an attacker to execute arbitrary code.

Root Cause: The lack of strict type checking in the application's input validation routines. The code likely uses a dynamic type system (common in JavaScript-based environments like OpenHarmony's JS/TS framework) without proper type guards.

Attack Vector: A local attacker with low privileges crafts a malicious input (e.g., a specially crafted intent, message, or file) that is passed to a vulnerable pre-installed app. The app processes this input, triggering the type confusion and subsequent memory corruption.

Impact: Successful exploitation allows the attacker to execute arbitrary code with the privileges of the pre-installed app. Since these apps often have elevated permissions (e.g., access to system services, sensors, or user data), the attacker can escalate privileges, steal sensitive information, or install persistent malware.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on the vulnerability description.

Vulnerable Code (JavaScript/TypeScript example):

function processInput(input) {
    // No type checking - assumes input is a string
    let length = input.length; // If input is an array, this works, but other operations may fail
    let result = input.toUpperCase(); // Type confusion: if input is not a string, this crashes or corrupts memory
    return result;
}

Patched Code (Hypothetical):

function processInput(input) {
    // Strict type checking
    if (typeof input !== 'string') {
        throw new TypeError('Expected a string');
    }
    let length = input.length;
    let result = input.toUpperCase();
    return result;
}

The patched version adds a typeof check to ensure the input is a string before performing string-specific operations. This prevents type confusion and memory corruption.

Exploitation & Lab Setup

Red Team (Exploitation):

Since no public exploit exists, the following is a conceptual approach:

1. Reconnaissance: Identify pre-installed apps on the target OpenHarmony device (e.g., via adb shell pm list packages).
2. Fuzzing: Use a fuzzer (e.g., AFL++ or a custom JS fuzzer) to send malformed inputs to the app's exposed interfaces (e.g., intents, IPC, or file parsing).
3. Trigger: Craft a payload that causes a type confusion. For example, send an array where a string is expected:

   // Malicious payload
   let maliciousInput = [1, 2, 3]; // Array instead of string
   vulnerableApp.processInput(maliciousInput);
   

4. Exploit: Use the memory corruption to overwrite a function pointer or return address, redirecting execution to shellcode.

Blue Team (Defense & Detection):

1. Monitor for crashes: Enable crash reporting and monitor for unusual app crashes (e.g., via logcat).
2. Input validation: Implement strict type checking in all pre-installed apps.
3. Sandboxing: Run pre-installed apps in a restricted sandbox with minimal permissions.
4. Behavioral analysis: Use EDR solutions to detect anomalous behavior, such as unexpected memory access patterns.

Indicators of Compromise (IOCs)

• File Hashes (SHA-256): None available (no known malware samples).
• Process Names: com.ohos.xxx (any pre-installed app process showing abnormal memory usage or crashes).
• Network Indicators: Unusual outbound connections from pre-installed apps (e.g., to unknown IPs).
• Log Entries: logcat entries showing TypeError, Segmentation fault, or SIGSEGV in pre-installed app processes.
• Registry/Config Changes: Modified system files or permissions in /system/app/ or /data/app/.

Detection Engineering

YARA Rule:

rule CVE_2025_25277_TypeConfusion {
    meta:
        description = "Detects potential exploitation of CVE-2025-25277 via type confusion in OpenHarmony apps"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-25277"
    strings:
        $s1 = "toUpperCase" nocase
        $s2 = "processInput" nocase
        $s3 = "TypeError" nocase
    condition:
        any of ($s1, $s2, $s3)
}

Sigma Rule:

title: CVE-2025-25277 Type Confusion Exploitation Attempt
id: 8a9b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects log entries indicating type confusion in OpenHarmony pre-installed apps
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-25277
logsource:
    product: openharmony
    service: logcat
detection:
    selection:
        - "TypeError"
        - "Segmentation fault"
        - "SIGSEGV"
    condition: selection
falsepositives:
    - Legitimate app crashes due to bugs
level: medium

Suricata Rule:

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-25277 Potential Exploitation - Type Confusion"; flow:to_server; content:"|00 01 02 03|"; depth:4; sid:1000001; rev:1;)

Note: The Suricata rule above is a placeholder. Real-world detection would require specific network signatures, which are not available for this CVE.

Remediation & Mitigation

1. Patch: Apply the official patch from OpenHarmony when released. Monitor the OpenHarmony security advisory page for updates.
2. Workaround: If patching is not possible, restrict local access to the device (e.g., disable USB debugging, enforce strong authentication).
3. App Hardening: Review and harden all pre-installed apps to include strict type checking and input validation.
4. Monitoring: Deploy the YARA and Sigma rules above to detect exploitation attempts.
5. Least Privilege: Run pre-installed apps with the minimum necessary permissions.

Valters IT