Ahnlab, a South Korean software company, simultaneously published a paper regarding Bisonal's activity in South Korea. In this case, the infection vector has changed from previous samples. The initial stage is a binary that drops a decoy document (Powerpoint or Excel document), a VisualBasic script and the packed Bisonal payload. The payload is dropped with a .jpg extension that's been renamed to ".exe. The payload has been packed with a new packer. The code of Bisonal is similar to the version of 2019