16 January 2020

Ryuk ransomware “wakes up” turned off devices using Wake-on-Lan feature


Ryuk ransomware “wakes up” turned off devices using Wake-on-Lan feature

Security researchers observed the Ryuk ransomware leveraging a special function called Wake-on-Lan to turn on the powered off devices on a compromised network in order to encrypt them.

Wake-on-Lan (WoL) is a feature for waking computers up from a very low power mode remotely by sending a network message.

According to SentinelLabs’ researcher Vitali Kremez who analyzed some of the recent samples of the Ryuk ransomware, when executing the malware spawns subprocesses with the argument '8 LAN'. This argument is used to scan the device’s ARP table to check if the listed entries of network devices were part of the “10.,” “172.16.” and/or “192.168” private IP address subnets.

If it finds an entry in the ARP table that is a part of any of the mentioned above networks, the malware will send a Wake-on-Lan (WoL) packet to the device's MAC address to awake the device. The WoL request is sent in the form of a 'magic packet' containing 'FF FF FF FF FF FF FF FF'. Once the WoL request is successful, Ryuk mounts the device’s C$ administrative share and encrypts the computer’s drive.

“This is how the group adapted the network-wide ransomware model to affect more machines via the single infection and by reaching the machines via WOL & ARP. It allows for more reach and less isolation and demonstrates their experience dealing with large corporate environments,” explained Kremez speaking to BleepingComputer.

To mitigate the risk of such attacks administrators are recommended to enable Wake-on-LAN packets only from administrative devices and workstations. This would allow administrators to continue using this feature, while adding some protection to the endpoints.


Back to the list

Latest Posts

Hackers probing the Internet for vulnerable Microsoft Exchange servers

Hackers probing the Internet for vulnerable Microsoft Exchange servers

Exchange servers admins are urged to patch their servers before hackers could get to them.
28 February 2020
New Wi-Fi chip bug affects over a billion of devices, including smartphones, tablets, laptops, and IoT gadgets

New Wi-Fi chip bug affects over a billion of devices, including smartphones, tablets, laptops, and IoT gadgets

Devices from Amazon, Apple, Google, and Samsung as well as some access points by Asus and Huawei, are found to be vulnerable to Kr00k.
27 February 2020
‘Cloud Snooper’ operation uses a unique combination of techniques to evade detection

‘Cloud Snooper’ operation uses a unique combination of techniques to evade detection

The attack involves piggybacking C2 traffic on a legitimate traffic, thus allowing to bypass firewalls.
26 February 2020