Hackers are using newly detected malware to backdoor Microsoft Exchange servers of government and military organizations from Europe, the Middle East, Asia, and Africa.

The malware, named SessionManager by Kaspersky researchers, who first detected it in early 2022, is a malicious native-code module for the tech giant’s Internet Information Services (IIS) web server software.

It has been used in the wild without being detected since at least March 2021, right after the start of last year’s notorious wave of ProxyLogon attacks.

“The SessionManager backdoor enables threat actors to keep persistent, update-resistant and rather stealth access to the IT (Information Technology) infrastructure of a targeted organization,” Kaspersky said on Thursday.

Session Manager has the following features:

  • dropping and managing arbitrary files on compromised servers
  • remote command execution on backdoored devices
  • connecting to endpoints within the victim’s local network and controlling the network traffic

Moreover, Kaspersky in April 2022 found that many of the malware samples detected earlier were still deployed on 34 servers of 24 organizations as late as June 2022.

After deployment, the malicious IIS module enables the attackers to harvest credentials from system memory, obtain information from the victims’ network and infected devices, and deliver more payloads.

According to victimology and the use of an HTTP (Hypertext Transfer Protocol) server-type backdoor variant called OwlProxy, Kaspersky security experts believe the SessionManager IIS backdoor was leveraged in these attacks by the Gelsemium group as part of a global espionage operation.

The Gelsemium APT (Advanced Persistent Threat) gang gained infamy for targeting governments, electronics manufacturers, and universities from East Asia and the Middle East and mostly operating under the radar.

For more information, read the original story in Bleepingcomputer.