OWASSRF in Microsoft Exchange Server
CVE-2022-41080, dubbed OWASSRF by public researchers, is an authenticated server-side request forgery vulnerability in on-premises Microsoft Exchange Server Outlook Web Access (OWA). The issue arises from OWA request handling that allows attacker-controlled input from the X-OWA-ExplicitLogonUser header to influence ExplicitSignOnAddress during backend URL construction. Reported vulnerable code paths include OwaProxyRequestHandler.GetTargetBackEndServerUrl and OwaEcpProxyRequestHandler.GetClientUrlForProxy, with UrlHelper.RemoveExplicitLogonFromUrlAbsolutePath removing the explicit logon component from the path via string replacement. By supplying a value beginning with "owa/" in X-OWA-ExplicitLogonUser and crafting a request such as /owa/test%40gmail.com/mapi/nspi, an authenticated attacker can cause the frontend to rewrite and proxy the request to backend Exchange endpoints such as /mapi/nspi. Researchers also stated the flaw can expose backend /powershell access through OWA, enabling access to Exchange PowerShell remoting surfaces that are normally not remotely reachable in this manner. Microsoft classifies the issue as an Exchange Server elevation of privilege vulnerability, but the technical primitive described in the supporting content is authenticated SSRF.
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Exploits
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No public exploit code observed for this vulnerability.
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Recent activity
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An on-premises Microsoft Exchange vulnerability, part of the OWASSRF exploit chain, used by Storm-1175 to gain initial access by exposing Exchange PowerShell via OWA.
An authenticated SSRF vulnerability in Microsoft Exchange OWA that can proxy attacker-controlled requests to backend Exchange endpoints such as /mapi/nspi and /powershell using the victim's authenticated context.
A Microsoft Exchange Server privilege escalation vulnerability rated Critical in the referenced Patch Tuesday set.
Critical elevation of privilege vulnerability in Microsoft Exchange Server.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.