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Weakness · High

CWE-918: Server-Side Request Forgery (SSRF)

What it is

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

22 exploited in the wildMITRE CWE 4.19.1

Severity (our rating)
High
Likelihood of exploit
Not rated by MITRE
Introduced during
Architecture and Design, Implementation
Exploited in the wild
22 known exploited CVEs

What an attacker can do

  • Read Application Data (Confidentiality)
  • Execute Unauthorized Code or Commands (Integrity)
  • Bypass Protection Mechanism (Access Control)

How to prevent it

MITRE lists no specific mitigation for this weakness. Treat it like its parent weaknesses below: validate input, keep the design simple and review the code where it could appear.

While the code is being fixed, a WAF in blocking mode stops SSRF payloads aimed at cloud metadata endpoints at the edge.

How to find it

  • Automated Static Analysis. Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

CWE-918 on MITRE's CWE site

Exploited in the wild: 22 CVEs

Vulnerabilities caused by CWE-918 that attackers have used, from CISA's Known Exploited Vulnerabilities catalog, newest first.

All known exploited vulnerabilities

The Dome

Block it at the edge while you fix it

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops SSRF payloads aimed at cloud metadata endpoints before they reach your application.

See the Dome

T Academy

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Source: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.