Advanced RATs exploit architectural blind spots and native tools to evade detection

A flaw in the Cursor AI editor allows malicious code in repositories to autorun on developer devices. This vulnerability can lead to malware execution, environment hijacking, and credential theft. The issue arises from Cursor disabling the Workspace Trust feature from VS Code, which prevents automatic task execution without explicit user consent. The flaw affects one million users who generate over a billion lines of code daily. The Cursor team has decided not to fix the issue, citing the need to maintain AI and other features. They recommend users enable Workspace Trust manually or use basic text editors for unknown projects. The flaw is part of a broader trend of prompt injections and jailbreaks affecting AI-powered coding tools.

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.

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.

APT28, a Russian state-sponsored threat group, has been using a new backdoor malware called NotDoor to target Microsoft Outlook. The malware exploits Outlook as a covert communication, data exfiltration, and malware delivery channel. NotDoor is a VBA macro that monitors incoming emails for specific trigger words. When triggered, it allows attackers to exfiltrate data, upload files, and execute commands on the victim's computer. The malware is delivered via a legitimate signed binary, Microsoft's OneDrive.exe, vulnerable to DLL sideloading. The backdoor was identified by researchers from Lab52, the threat intelligence arm of Spanish cybersecurity firm S2 Grupo. The malware has been deployed against companies in NATO member countries, using advanced techniques to evade detection and maintain persistence. NotDoor supports multiple commands for data exfiltration and file uploads, and uses Base64-encoded PowerShell commands for various operations. The malware creates a staging folder in the %TEMP% directory to store and exfiltrate files, encoding them with custom encryption before sending via email. APT28's attacks involve the abuse of Microsoft Dev Tunnels for C2 infrastructure, providing stealth and rapid infrastructure rotation. The attack chain includes the use of bogus Cloudflare Workers domains to distribute additional payloads, demonstrating a high level of specialized design and obfuscation.