CVE-2021-27670

What is this vulnerability?

CVE-2021-27670 is categorized as a critical Server-Side Request Forgery (SSRF) flaw with a CVSS base score of 9.8. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

Appspace 6.2.4 allows SSRF via the api/v1/core/proxy/jsonprequest url parameter.

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

Impact on Systems

✅ Unauthorized Data Access: Attackers can bypass authorization controls to access other users' data or administrative endpoints.

✅ Account Takeover: Broken authentication or authorization may enable full account compromise without valid credentials.

✅ API Abuse: Exploiting this vulnerability enables mass data harvesting or destructive operations through unprotected API endpoints.

How to Fix and Mitigate CVE-2021-27670

1. Apply Vendor Patches: Upgrade affected components to their latest, non-vulnerable versions immediately.
2. Implement Input Validation: Ensure all user-supplied data is validated, sanitized, and type-checked before processing.
3. Deploy Runtime Protection: Use Precogs continuous monitoring to detect exploitation attempts in real time.
4. Audit Dependencies: Review and update all third-party libraries and transitive dependencies.

Defending with Precogs AI

Appspace contains an insecure direct object reference (IDOR) or authentication bypass vulnerability. Attackers manipulate request parameters to access data or administrative functions belonging to other users. Precogs API Security Engine comprehensively audits resource-level authorization logic.

Use Precogs to continuously scan your codebase, binaries, APIs, and infrastructure for this vulnerability class and related attack patterns. Our AI-powered detection engine combines static analysis with threat intelligence to identify exploitable weaknesses before attackers do.

Start scanning with Precogs →

Vulnerability Code Signature

Attack Data Flow

Vulnerable Code Pattern

// ❌ VULNERABLE: Server-Side Request Forgery
app.get('/proxy', async (req, res) => {
  const targetUrl = req.query.url;
  // Taint sink: unvalidated outbound request
  const response = await fetch(targetUrl);
  res.send(await response.text());
});

Secure Code Pattern

// ✅ SECURE: Allowlist validation
const ALLOWED_DOMAINS = ['api.partner.com'];
app.get('/proxy', async (req, res) => {
  const targetUrl = new URL(req.query.url);
  
  if (!ALLOWED_DOMAINS.includes(targetUrl.hostname)) {
    return res.status(403).send("Domain not allowed");
  }
  
  // Sanitized outbound request
  const response = await fetch(targetUrl.href);
  res.send(await response.text());
});

How Precogs Detects This

Precogs API Security Engine actively detects SSRF vulnerabilities by tracking unvalidated URL sinks and enforcing strict allowlist policies.\n