Overview
Microsoft Exchange 2019 Cumulative Update 23 and earlier versions are vulnerable to a server-side request forgery (SSRF) attack and remote code execution. An authenticated attacker can use the combination of these two vulnerabilities to elevate privileges and execute arbitrary code on the target Exchange server.
Description
Microsoft Exchange Server's Autodiscover service is a web service widely available to any Microsoft Exchange Web Services (EWS) client. Since Microsoft Exchange version 2016, the Autodiscover service has become an integral part of the Microsoft Exchange system, and it is no longer independently provided by a Client Access server. The Autodiscover service and a number of other privileged mailbox services are hosted on the default Internet Information Services server running on the Mailbox server.
Cybersecurity company GTSC observed an abuse of the Autodiscover service in August of 2022 using a crafted URL SSRF attack, similar to the earlier ProxyShell vulnerability reported in August 2021. The observed attack appears to have implemented CVE-2022-41040 to gain privileged access and CVE-2022-41082 to perform remote code execution via PowerShell. Microsoft Security Research Center has acknowledged the vulnerability and provided guidance for mitigation. The guidance highlights that Microsoft Exchange Online customers will be provided with detection and mitigation defenses automatically from Microsoft's managed Infrastructure, informing them of any attempts to exploit these vulnerabilities.
Impact
An authenticated remote attacker can perform SSRF attacks ..
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