Silver Fox Deploys ABCDoor Malware via Tax Phishing in India and Russia

The China-based cybercrime group Silver Fox has launched a new campaign deploying ABCDoor malware, primarily targeting organizations in India and Russia. The Hacker News reports that the initial wave in December 2025 involved sophisticated phishing emails impersonating the Indian Income Tax Department. A subsequent, nearly identical campaign then targeted Russian entities.

This isn’t just opportunistic spam. Silver Fox is known for its persistent, financially motivated operations. The use of a new, custom backdoor like ABCDoor indicates a strategic investment in maintaining stealthy, long-term access to compromised networks. Their tactic of mimicking tax authorities is a classic social engineering play, highly effective due to the inherent urgency and perceived legitimacy of government communications.

For defenders, this highlights a critical problem: attackers are constantly refining their initial access vectors. Phishing remains the top vector for a reason. Silver Fox’s ability to tailor campaigns for different geographies with convincing lures means organizations need to move beyond generic awareness training. Assume your users will click. Focus on robust endpoint detection, network segmentation, and rapid incident response to contain the inevitable compromise.