CVE-2021-26855

CVE Published	2021-03-03
Related CWE(s)	CWE-918: Server-Side Request Forgery (SSRF)
Related Vendor(s)	microsoft
Related Product(s)	exchange_server
Exploitation Reported (CISA KEV)	2021-11-03
CVSS 3 Base Score	9.8 (CRITICAL)
CVSS 3 Attack Complexity	LOW
CVSS 3 Attack Vector	NETWORK

Microsoft Exchange Server Remote Code Execution Vulnerability

Cyber Threat Graph Context

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Threat Reports Related to CVE-2021-26855

Report

HAFNIUM targeting Exchange Servers with 0-day exploits

In March 2021 Microsoft detected multiple zero-day exploits being used as part of a widespread campaign by HAFNIUM / Silk Typhoon. This report ...

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Associated CAPEC Patterns

Server Side Request Forgery (CAPEC-664)

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.

References

CVE.org

View more information about CVE-2021-26855 on the official MITRE CVE website.

NIST National Vulnerability Database

CVE-2021-26855 on the NIST NVD.

CISA Known Exploited Vulnerabilities