U.S., U.K. and Australia Warn of Iranian APTs Targeting Fortinet, Microsoft Exchange Flaws

17 November 2021

U.S., U.K. and Australia Warn of Iranian APTs Targeting Fortinet, Microsoft Exchange Flaws

Iranian Threat Actors Target U.S. Critical Infrastructure, Australian Organizations

Iranian state-sponsored threat actors are exploiting Fortinet and Microsoft Exchange vulnerabilities in attacks targeting critical infrastructure in the United States, as well as Australian organizations, warns a joint advisory from government agencies in the U.S., U.K., and Australia.

The adversaries have been observed exploiting Fortinet vulnerabilities in attacks since at least March 2021, as well as targeting a Microsoft Exchange ProxyShell vulnerability since October 2021, for initial access.

Targets include organizations in the transportation, healthcare, and public health sectors in the U.S., as well as Australian entities, reads the joint advisory from the Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), the Australian Cyber Security Centre (ACSC), and the United Kingdom’s National Cyber Security Centre (NCSC).

In March 2021, Iranian government-sponsored APT actors were observed targeting Fortinet FortiOS vulnerabilities such as CVE-2018-13379, CVE-2019-5591, and CVE-2020-12812 to gain access to vulnerable networks.

In May 2021, the same adversary exploited a vulnerability in a Fortigate appliance to compromise a web server hosting the domain for a U.S. municipal government and created an account named elie to maintain access to the resource.

In June 2021, the Iranian APTs exploited a Fortigate appliance to compromise networks associated with a U.S.-based hospital that provides healthcare to children. IP addresses associated with Iranian government cyber activity were used in additional malicious activity against the network.

Starting October 2021, the Iranian government-linked adversaries exploited CVE-2021-34473, a Microsoft Exchange ProxyShell vulnerability, for initial access to their targets’ environments. The APT group used the same vulnerability in attacks against Australian entities, ACSC believes.

Following initial access, the attackers likely modified Task Scheduler tasks for payload execution, and created new accounts on domain controllers, active directories, servers, and workstations to achieve persistence.

During their attacks, the adversaries employed various tools for credential harvesting (Mimikatz), privilege escalation (WinPEAS), data archiving (WinRAR), and file transfer (FileZilla). SharpWMI (Windows Management Instrumentation) was also employed.

In their joint advisory, the FBI, CISA, ACSC, and NCSC urge organizations to immediately apply patches for the targeted vulnerabilities. They also provide indicators of compromise (IoCs) to help detect potential compromise, and a series of mitigation recommendations to strengthen networks against potential attacks.