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

Description

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.

Extended Description

N/A

ThreatScore

Threat Mapped score: 0.0

Industry: Finiancial

Threat priority: Unclassified

Observed Examples (CVEs)

CVE: CVE-2023-32786

Chain: LLM integration framework has prompt injection (CWE-1427) that allows an attacker to force the service to retrieve data from an arbitrary URL, essentially providing SSRF (CWE-918) and potentially injecting content into downstream tasks.
CVE: CVE-2021-26855 — KEV

Server Side Request Forgery (SSRF) in mail server, as exploited in the wild per CISA KEV.
CVE: CVE-2021-21973 — KEV

Server Side Request Forgery in cloud platform, as exploited in the wild per CISA KEV.
CVE: CVE-2016-4029

Chain: incorrect validation of intended decimal-based IP address format (CWE-1286) enables parsing of octal or hexadecimal formats (CWE-1389), allowing bypass of an SSRF protection mechanism (CWE-918).
CVE: CVE-2002-1484

Web server allows attackers to request a URL from another server, including other ports, which allows proxied scanning.
CVE: CVE-2004-2061

CGI script accepts and retrieves incoming URLs.
CVE: CVE-2010-1637

Web-based mail program allows internal network scanning using a modified POP3 port number.
CVE: CVE-2009-0037

URL-downloading library automatically follows redirects to file:// and scp:// URLs

Related Attack Patterns (CAPEC)

CAPEC-664

Attack TTPs

N/A

Modes of Introduction

Phase	Note
Architecture and Design	N/A
Implementation	N/A

Common Consequences

Impact: Read Application Data — Notes:
Impact: Execute Unauthorized Code or Commands — Notes:
Impact: Bypass Protection Mechanism — Notes: By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.

Potential Mitigations

None listed.

Applicable Platforms

None (Not Language-Specific, Undetermined)

Demonstrative Examples

N/A

Notes

Relationship: CWE-918 (SSRF) and CWE-611 (XXE) are closely related, because they both involve web-related technologies and can launch outbound requests to unexpected destinations. However, XXE can be performed client-side, or in other contexts in which the software is not acting directly as a server, so the "Server" portion of the SSRF acronym does not necessarily apply.

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