CVE-2025-6969

Executive Summary

CVE-2025-6969 is a denial-of-service (DoS) vulnerability in OpenHarmony v5.1.0 and prior versions. The flaw allows a local attacker to cause a denial of service through improper input validation. With a CVSS score of 5.0 (Medium), the vulnerability requires local access and low privileges, but no user interaction. The impact is limited to availability, with no confidentiality or integrity compromise. The EPSS score is 0.0%, indicating a very low probability of exploitation in the wild. No public proof-of-concept or exploit code is available at this time.

CVSS Breakdown & Threat Level

• CVSS Score: 5.0 (Medium)
• Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
• Attack Vector: Local (AV:L) – The attacker must have local access to the system.
• Attack Complexity: Low (AC:L) – No special conditions are required.
• Privileges Required: Low (PR:L) – The attacker needs basic user privileges.
• User Interaction: None (UI:N) – No user action is needed.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: None (C:N)
• Integrity Impact: None (I:N)
• Availability Impact: High (A:H) – Successful exploitation leads to a denial of service.

Threat Level: Medium. The vulnerability is locally exploitable with low privileges, but the lack of public exploits and low EPSS score reduces immediate risk.

Deep Dive & Mechanics

The vulnerability resides in improper input validation within OpenHarmony. A local attacker can craft a malicious input that, when processed by the system, causes a denial of service. The exact component is not specified, but it likely involves a system service or driver that fails to handle malformed data correctly. The attack could lead to system crashes, resource exhaustion, or service unavailability.

Vulnerable vs. Patched Code

No specific code snippets are available due to the lack of patch information. However, the vulnerability is related to improper input validation. A typical fix would involve adding input sanitization and bounds checking.

Vulnerable Code (Hypothetical):

void process_input(char *input) {
    char buffer[256];
    strcpy(buffer, input); // No bounds checking
}

Patched Code (Hypothetical):

void process_input(char *input) {
    char buffer[256];
    strncpy(buffer, input, sizeof(buffer) - 1);
    buffer[sizeof(buffer) - 1] = '\0';
}

Exploitation & Lab Setup

Red Team

Since no public exploit exists, a red team would need to reverse-engineer the vulnerable component. The attack vector is local, so the attacker must have a user account on the target system. The exploit would involve sending a specially crafted input to the vulnerable service.

Hypothetical Exploit (Python):

import socket

def exploit(target_ip, target_port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.connect((target_ip, target_port))
    payload = b"A" * 10000  # Large payload to cause overflow
    sock.send(payload)
    sock.close()

if __name__ == "__main__":
    exploit("127.0.0.1", 8080)

Blue Team

Blue team should monitor for unusual local process behavior, such as crashes or high resource usage. Implement input validation and rate limiting on local services.

Detection Steps:

1. Monitor system logs for crashes or service restarts.
2. Use file integrity monitoring to detect changes to critical binaries.
3. Implement application whitelisting to prevent unauthorized code execution.

Indicators of Compromise (IOCs)

• File Hashes: None available.
• Network Indicators: None (local attack).
• System Logs: Unexpected crashes or service restarts in /var/log/syslog or dmesg.
• Process Anomalies: High CPU or memory usage by system processes.

Detection Engineering

YARA Rule

rule CVE_2025_6969_OpenHarmony_DOS {
    meta:
        description = "Detects potential exploitation of CVE-2025-6969"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $s1 = "OpenHarmony" nocase
        $s2 = "5.1.0" nocase
    condition:
        $s1 and $s2
}

Sigma Rule

title: CVE-2025-6969 OpenHarmony DoS Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects local DoS attempts against OpenHarmony
author: Valters IT
logsource:
    product: linux
    service: syslog
detection:
    selection:
        - EventID: 1001
          Message: "*crash*"
        - EventID: 6005
          Message: "*service*"
    condition: selection
falsepositives:
    - Legitimate system crashes
level: medium

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-6969 OpenHarmony DoS Attempt"; flow:to_server; content:"OpenHarmony"; nocase; content:"5.1.0"; nocase; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

1. Patch: Apply the official patch from OpenHarmony when available.
2. Workaround: Restrict local user access to the vulnerable service.
3. Input Validation: Implement strict input validation and bounds checking.
4. Monitoring: Enable logging and monitoring for unusual system behavior.
5. Least Privilege: Ensure users have only necessary privileges.

Valters IT