We have been reporting Mirai Botnet since 2019 and recent activity suggests that Dark Mirai Botnet is being spread using a vulnerability CVE-2021-41653 which effects TP-LINK TL-WR840N EU (V5) routers. A working PoC of the vulnerability was also published by security researcher. This new exploit was added by the botnet operators to their operation only two weeks after the TP-Link firmware update was released. Authentication on the router is required for successful exploitation.
The PING function on the TP-Link TL-WR840N EU v5 router with firmware through TL-WR840N(EU)_V5_171211 is vulnerable to remote code execution via a crafted payload in an IP address input field.
Like the Mirai botnet, Dark Mirai determines the victim’s architecture to fetch and download the matching payload.
Once the malware is installed, a command from the C&C (Command and Control) server actions to perform a variation of DoS (Denial of Service) attack.
Upgrade your firmware to the latest version of TL-WR840N(EU)_V5_211109 from vendor website here: