CWE-918 Software Weakness Details

CWE-918

Name

Server-Side Request Forgery (SSRF)

Status

Incomplete

Published

2013-02-21
00h00 +00:00

Modified

2024-11-19
00h00 +00:00

Official links

CWE Mitre.org

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Name: Server-Side Request Forgery (SSRF)

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.

General Informations

Modes Of Introduction

Architecture and Design
Implementation

Applicable Platforms

Language

Class: Not Language-Specific (Undetermined)

Technologies

Name: Web Server (Undetermined)

Common Consequences

Scope	Impact	Likelihood
Confidentiality	Read Application Data
Integrity	Execute Unauthorized Code or Commands
Access Control	Bypass Protection Mechanism Note: 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.

Observed Examples

References	Description
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-2021-26855	Server Side Request Forgery (SSRF) in mail server, as exploited in the wild per CISA KEV.
CVE-2021-21973	Server Side Request Forgery in cloud platform, as exploited in the wild per CISA KEV.
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-2002-1484	Web server allows attackers to request a URL from another server, including other ports, which allows proxied scanning.
CVE-2004-2061	CGI script accepts and retrieves incoming URLs.
CVE-2010-1637	Web-based mail program allows internal network scanning using a modified POP3 port number.
CVE-2009-0037	URL-downloading library automatically follows redirects to file:// and scp:// URLs

Detection Methods

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.)
Effectiveness : High

Vulnerability Mapping Notes

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-664	Server Side Request Forgery An adversary exploits improper input validation by submitting maliciously crafted input to a target application running on a server, with the goal of forcing the server to make a request either to itself, to web services running in the server’s internal network, or to external third parties. If successful, the adversary’s request will be made with the server’s privilege level, bypassing its authentication controls. This ultimately allows the adversary to access sensitive data, execute commands on the server’s network, and make external requests with the stolen identity of the server. Server Side Request Forgery attacks differ from Cross Site Request Forgery attacks in that they target the server itself, whereas CSRF attacks exploit an insecure user authentication mechanism to perform unauthorized actions on the user's behalf.

NotesNotes

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.

References

REF-913

SSRF vs. Business-critical applications: XXE tunneling in SAP
Alexander Polyakov, Dmitry Chastukhin.
https://media.blackhat.com/bh-us-12/Briefings/Polyakov/BH_US_12_Polyakov_SSRF_Business_Slides.pdf

REF-914

SSRF vs. Business-critical Applications. Part 1: XXE Tunnelling in SAP NetWeaver
Alexander Polyakov, Dmitry Chastukhin, Alexey Tyurin.
http://erpscan.com/wp-content/uploads/2012/08/SSRF-vs-Businness-critical-applications-whitepaper.pdf

Submission

Name	Organization	Date	Date release	Version
CWE Content Team	MITRE	2013-02-17 +00:00	2013-02-21 +00:00	2.4

Modifications

Name	Organization	Date	Comment
CWE Content Team	MITRE	2015-12-07 +00:00	updated Relationships
CWE Content Team	MITRE	2017-01-19 +00:00	updated Relationships
CWE Content Team	MITRE	2017-11-08 +00:00	updated Applicable_Platforms, References
CWE Content Team	MITRE	2018-03-27 +00:00	updated References
CWE Content Team	MITRE	2019-06-20 +00:00	updated Relationships
CWE Content Team	MITRE	2020-02-24 +00:00	updated Applicable_Platforms, Relationships
CWE Content Team	MITRE	2021-07-20 +00:00	updated References, Related_Attack_Patterns, Relationships
CWE Content Team	MITRE	2021-10-28 +00:00	updated Relationships
CWE Content Team	MITRE	2022-06-28 +00:00	updated Observed_Examples, Relationships
CWE Content Team	MITRE	2022-10-13 +00:00	updated Observed_Examples
CWE Content Team	MITRE	2023-04-27 +00:00	updated Detection_Factors, References, Relationships
CWE Content Team	MITRE	2023-06-29 +00:00	updated Mapping_Notes, Relationships
CWE Content Team	MITRE	2024-11-19 +00:00	updated Alternate_Terms, Common_Consequences, Description, Diagram, Observed_Examples, Relationships

CWE-918 Detail