ScarCruft's RokRAT Malware Campaign Targeting South Korean Academics

The ChillyHell macOS backdoor malware, initially observed in 2022, has resurfaced with a new version. This modular backdoor allows attackers remote access and the ability to drop payloads, brute-force passwords, and evade detection. The malware, disguised as an executable applet, was discovered on VirusTotal and had been publicly hosted on Dropbox since 2021. The malware employs multiple persistence mechanisms and communicates over various protocols, making it highly flexible. It can exfiltrate data, drop additional payloads, and enumerate user accounts. Apple has revoked the notarization of the developer certificates associated with the malware. The resurgence of ChillyHell highlights the increasing threat landscape for macOS, emphasizing the need for robust security measures. A new Go-based remote access trojan (RAT) named ZynorRAT has been discovered, targeting Windows and Linux systems. ZynorRAT uses a Telegram bot for command and control and supports a wide range of functions, including file exfiltration and system enumeration.

The House Select Committee on China has issued a warning about ongoing cyber espionage campaigns by China-linked APT41 targeting U.S. trade officials and related organizations. The attacks involve phishing emails impersonating U.S. officials to steal sensitive information. The campaign coincides with contentious U.S.-China trade negotiations. The threat actors exploit software and cloud services to cover their tracks. The attacks aim to steal valuable data and gain unauthorized access to systems. The committee has noted similar tactics used in previous campaigns, including a January 2025 spear-phishing attempt targeting committee staffers. The FBI is investigating the ongoing cyber espionage campaign. APT41 has been known to conduct financially motivated activities in addition to state-sponsored espionage. The group has targeted various sectors, including logistics, utilities, healthcare, high-tech, and telecommunications. The committee recommends user awareness phishing training, mandatory multifactor authentication, FIDO keys, and appropriate email gateway and endpoint security tools to mitigate such attacks.

Threat actors are leveraging HTTP client tools like Axios and Microsoft's Direct Send feature to execute advanced phishing campaigns targeting Microsoft 365 environments. These campaigns have demonstrated a 70% success rate, bypassing traditional security defenses and exploiting authentication workflows. The attacks began in July 2025 and have targeted executives and managers in various sectors, including finance, healthcare, and manufacturing. The phishing campaigns use compensation-themed lures to trick recipients into opening malicious PDFs containing QR codes that direct users to fake login pages. Additionally, a phishing-as-a-service (PhaaS) offering called Salty 2FA is being used to steal Microsoft login credentials and bypass multi-factor authentication (MFA). The Salty2FA kit includes advanced features such as subdomain rotation, dynamic corporate branding, and sophisticated evasion tactics to enhance its effectiveness and evade detection. Salty2FA activity began gaining momentum in June 2025, with early traces possibly dating back to March–April 2025. The campaigns have been active since late July 2025 and continue to this day, generating dozens of fresh analysis sessions daily. Salty2FA targets industries including finance, energy, telecom, healthcare, government, logistics, IT consulting, education, construction, chemicals, industrial manufacturing, real estate, consulting, metallurgy, and more.

A new variant of a TOR-based cryptojacking campaign targets misconfigured Docker APIs to propagate malware. The attack chain involves exploiting exposed Docker instances to deploy XMRig miners and reconnaissance tools. The malware also scans for additional ports and attempts to propagate via Telnet and Chromium remote debugging ports. The campaign may be setting up a complex botnet. The attack leverages Base64-encoded payloads and TOR domains for anonymity. It includes a dropper written in Go that parses user login information and uses Masscan for further propagation. The malware's source code includes an emoji, suggesting it may have been crafted using a large language model (LLM). The attackers mount the host root to the fresh container, allowing them to manipulate the host system and escape the container. The attackers modify the SSH configuration of the host system to elevate privileges and provide backdoor access. The attackers create a cron job that executes every minute to block access to the Docker API’s port 2375, denying other attackers future access to the exposed instance. The threat actors deploy tools to perform mass scans for other open 2375 ports, which are used for malware propagation through the creation of new containers using the identified exposed APIs. The malware installs curl and tor, launches a Tor daemon, and waits for confirmation of the connection by accessing Amazon's checkip.amazonaws.com service over a SOCKS5 proxy. The malware appends an attacker-controlled public key to /root/.ssh/authorized_keys on the mounted host filesystem to enable persistent SSH access. The malware writes a base64-encoded cron job on the host, which executes every minute and blocks external access to port 2375 using available firewall utilities. The malware downloads a Zstandard-compressed Go binary over Tor, decompresses it, and runs it as a dropper. The Go binary parses the host’s utmp file to identify logged-in users. The malware attempts to infect other exposed Docker APIs and removes competitor containers after gaining access. The malware includes inactive logic for exploiting Telnet (port 23) using default router credentials and for interacting with Chrome’s remote debugging interface (port 9222). The malware's behavior suggests it is an initial version of a complex botnet with capabilities for lateral movement, persistence, and potential future expansion for credential theft and browser hijacking. The campaign highlights the importance of securing Docker APIs and segmenting networks to prevent such attacks.

A new malware campaign, tracked as MostereRAT, targets Japanese Windows users with sophisticated evasion techniques. MostereRAT disables antivirus and endpoint defenses, uses an obscure programming language, and abuses legitimate remote access tools to maintain persistent control over compromised systems. The malware's capabilities include privilege escalation, keylogging, data exfiltration, and the creation of hidden administrator accounts. The campaign's long-term objectives and the full extent of its impact remain unclear. MostereRAT employs Easy Programming Language (EPL) to evade detection and uses Windows Filtering Platform (WFP) filters to block security telemetry. The malware deploys legitimate remote access tools like AnyDesk, TigerVNC, and TightVNC, making it difficult to detect. The campaign highlights the importance of removing local administrator privileges and blocking unapproved remote access tools to reduce the attack surface. The malware uses mutual TLS (mTLS) to secure command-and-control (C2) communications and can run as TrustedInstaller, a built-in Windows system account with elevated permissions. MostereRAT can monitor foreground window activity associated with Qianniu - Alibaba's Seller Tool, facilitate RDP logins, and create hidden administrator accounts.