A newly discovered malware, OtterCookie, is being used in a malicious campaign known as Contagious Interview, which has been targeting software developers with fake job offers. The campaign, attributed to North Korean threat actors, has been active since at least December 2022. Researchers from cybersecurity firms Palo Alto Networks and NTT Security Japan have reported that OtterCookie is now one of the main payloads used in this operation, alongside other malware like BeaverTail. This new variant was first observed in September 2024, with a more recent version emerging in November 2024.
OtterCookie is delivered through malicious Node.js projects or npm packages downloaded from trusted platforms like GitHub and Bitbucket, which are often used by developers. The malware operates by using Socket.IO WebSocket to establish a secure connection with its command-and-control (C2) infrastructure. Once activated, the malware silently waits for commands, enabling attackers to execute various data theft activities, such as searching for cryptocurrency wallet keys and stealing clipboard contents. This exfiltration of sensitive information increases the severity of the attack, especially for developers who may store personal and professional data on their devices.
The malware’s September 2024 version included functionality to search for Ethereum private keys using regular expressions. However, the November 2024 variant saw a shift in the malware’s operation, where these commands are now executed remotely through the C2 server. OtterCookie’s flexibility and ability to target multiple forms of sensitive data make it a highly effective tool for attackers. The malware also uses reconnaissance commands like ls and cat to explore the environment, suggesting that its operators may aim to gain deeper access for further infiltration or lateral movement within compromised networks.
As the Contagious Interview campaign evolves, it highlights the ongoing risk to software developers from seemingly legitimate job offers that conceal malicious intent. Developers should be vigilant when engaging with potential employers, ensuring they verify any job opportunities carefully. It is also crucial for developers to avoid running untrusted code on their personal or work computers, as this could lead to significant data breaches. Regular updates to security measures and enhanced awareness of such threats are essential to mitigating the risks posed by campaigns like Contagious Interview and malware like OtterCookie.
