An unknown Chinese-speaking advanced persistent threat (APT) has been associated to a new campaign targeting betting firms in South East Asia, specifically Taiwan, the Philippines, and Hong Kong.
The campaign, which Avast dubs Operation Dragon Castling (ODC), is exploiting a security loophole (CVE-2022-24934) in WPS Office to deploy a backdoor on the targeted systems. The vulnerability has since been addressed by Kingsoft Office, the developers of the office software. However, with 1.2 billion WPS Office downloads around the globe, there are likely a high number of systems open to compromise.
According to Avast researchers, the bug was exploited to deploy a malicious binary from a fake update server with the domain update.wps[.]cn that triggers a multi-stage infection chain that leads to the deployment of intermediate payloads and allows for privilege escalation before finally deploying the Proto8 module.
"The core module is a single DLL that is responsible for setting up the malware's working directory, loading configuration files, updating its code, loading plugins, beaconing to [command-and-control] servers, and waiting for commands," Avast researchers Luigino Camastra, Igor Morgenstern, Jan Holman explained.
Proto8’s plugin-based technique applied to prolong its functionality permits the malware to achieve persistence, bypass user account control (UAC) mechanisms, develop new backdoor accounts, and even execute arbitrary commands on the infected program.
While researchers haven’t linked this malicious campaign to any known actors, they believe it is the work of a Chinese APT either looking to gather intelligence or achieve financial gains. Considering the nature of the targets, which is betting companies, the motive of the threat actors may have been to steal financial credentials or take over accounts and cash out escrow balances.
The techniques and the powerful toolset employed in the campaign reflect a skillful adversary, so not being able to make attributions with high confidence is somewhat expected. However, this isn’t the first instance that China-sponsored hackers have targeted betting firms.
Last year in January 2021, Chinese hackers targeted gambling firms that have been promoting their products to Chinese nationals without authorization. Attackers demanded at least $100 million be paid in Bitcoin to restore access to gambling operators’ servers, but companies remained adamant in the face of the threat and never paid a penny.
