Considering the ongoing tensions between India and China, as well as the new security laws over Hong Kong, we believe this new campaign is operated by a Chinese state-sponsored actor. this may be a Chinese APT group that has been active since at least 2014. The ampaign was most likely carried out through spear phishing emails. The .rar file (Mail security check.rar)
The document uses template injection to download a remote template from the following URL
The downloaded template uses the dynamic data exchange (DDE) protocol to execute malicious commands, which are encoded within the document’s content
Another variant from the attack used by the Chinese APT group in this campaign focused on issues happening in Hong Kong. The file was embedded within an archive file named “Boris Johnson Pledges to Admit 3 Million From Hong Kong to U.K.rar”.
The dropped executable (ff.exe) is a new variant of a loader called MgBot that drops and loads the final payload. This loader pretends to be a Realtek Audio Manager tool. The loader starts its process by escalating privilege through a UAC bypass using the CMSTPLUA COM interface.
MgBot uses several anti-analysis and anti-virtualization techniques. The code is self modifying which means it alters its code sections during runtime.