1. Operation Exchange Marauder: Active Exploitation of Multiple Zero-Day Microsoft Exchange Vulnerabilities

    [UPDATE] March 8, 2021 – Since original publication of this blog, Volexity has now observed that cyber espionage operations using the SSRF vulnerability CVE-2021-26855 started occurring on January 3, 2021, three days earlier than initially posted. Volexity is seeing active in-the-wild exploitation of multiple Microsoft Exchange vulnerabilities used to steal e-mail and compromise networks. These attacks appear to have started as early as January 6, 2021. In January 2021, through its Network Security Monitoring service, Volexity detected anomalous activity from two of its customers’ Microsoft Exchange servers. Volexity identified a large amount of data being sent to IP addresses it believed were not tied to legitimate users. A closer inspection of the IIS logs from the Exchange servers revealed rather alarming results. The logs showed inbound POST requests to valid files associated with images, JavaScript, cascading style sheets, and fonts used by Outlook Web Access (OWA). It was initially suspected the […]

  2. Microsoft Exchange Control Panel (ECP) Vulnerability CVE-2020-0688 Exploited

    On February 11, 2020, as part of Patch Tuesday, Microsoft released cumulative updates and a service pack that addressed a remote code execution vulnerability found in Microsoft Exchange 2010, 2013, 2016, and 2019. The vulnerability was discovered by an anonymous security researcher and reported to Microsoft by way of Trend Micro’s Zero Day Initiative. Two weeks after the security updates were released, the Zero Day Initiative published a blog post providing more details on the vulnerability. The post made it clear that an attacker could exploit a vulnerable Exchange server if the following three criteria were met: The Exchange Server had not been patched since February 11, 2020. The Exchange Control Panel (ECP) interface was accessible to the attacker. The attacker has a working credential that allows them to access the Exchange Control Panel in order to collect the ViewStateKey from the authenticated session cookie as well as the __VIEWSTATEGENERATOR […]