Malicious Android Apps with 19M Installs Removed from Google Play

A new Android Trojan named Klopatra has been identified, capable of performing unauthorized bank transfers while the device is inactive. The malware targets users in Italy and Spain, with over 3,000 devices infected. Klopatra disguises itself as the Mobdro streaming app and IPTV applications, leveraging their popularity to bypass security measures. It employs advanced techniques to evade detection and analysis, including anti-sandboxing methods, a commercial packer, and Hidden Virtual Network Computing (VNC) for remote control. The Trojan operates during nighttime hours, draining victims' bank accounts without alerting them. Klopatra uses Accessibility Services to gain extensive control over the device, allowing attackers to simulate user interactions remotely. It captures screenshots, records screen activity, and overlays fake login screens to steal credentials. The malware checks for device inactivity and charging status before executing its operations, ensuring the victim remains unaware until the next day. The malware is operated by a Turkish-speaking criminal group as a private botnet, with 40 distinct builds discovered since March 2025. The malware integrates Virbox, a commercial-grade code protector, to obstruct reverse-engineering and analysis. It uses native libraries to reduce its Java/Kotlin footprint and employs NP Manager string encryption in recent builds. Klopatra features several anti-debugging mechanisms, runtime integrity checks, and emulator detection capabilities. The malware supports all required remote actions for performing manual bank transactions, including simulating taps, swiping, and long-pressing. Klopatra uses Cloudflare to hide its digital tracks, but a misconfiguration exposed origin IP addresses, linking the C2 servers to the same provider. The malware has been linked to two campaigns, each counting 3,000 unique infections.

A new variant of the XCSSET macOS malware has been detected, targeting Xcode developers with enhanced features. This variant includes improved browser targeting, clipboard hijacking, and persistence mechanisms. The malware spreads by infecting Xcode projects, stealing cryptocurrency, and browser data from infected devices. The malware uses run-only compiled AppleScripts for stealthy execution and employs sophisticated encryption and obfuscation techniques. It incorporates new modules for data exfiltration, persistence, and clipboard monitoring. The malware has been observed in limited attacks, with Microsoft sharing findings with Apple and GitHub to mitigate the threat. Developers are advised to keep macOS and apps up to date and inspect Xcode projects before building them.

The UNC5221 activity cluster, attributed to suspected Chinese hackers, has been using the BRICKSTORM malware in long-term espionage operations against U.S. organizations in the technology, legal, SaaS, and BPO sectors. The malware, a Go-based backdoor, has been active for over a year, with an average dwell time of 393 days. It has been used to steal data from various sectors, including SaaS providers and BPOs. The attackers exploit vulnerabilities in edge devices and use anti-forensics techniques to avoid detection. The malware serves multiple functions, including web server, file manipulation, dropper, SOCKS relay, and shell command execution. It targets appliances without EDR support, such as VMware vCenter/ESXi, and uses legitimate traffic to mask its C2 communications. The attackers aim to exfiltrate emails and maintain stealth through various tactics, including removing the malware post-operation to hinder forensic investigations. The attackers use a malicious Java Servlet Filter (BRICKSTEAL) on vCenter to capture credentials, and clone Windows Server VMs to extract secrets. The stolen credentials are used for lateral movement and persistence, including enabling SSH on ESXi and modifying startup scripts. The malware exfiltrates emails via Microsoft Entra ID Enterprise Apps, utilizing its SOCKS proxy to tunnel into internal systems and code repositories. UNC5221 focuses on developers, administrators, and individuals tied to China's economic and security interests. Mandiant has released a free scanner script to help defenders detect BRICKSTORM. The BRICKSTORM backdoor is under active development, with a variant featuring a delay timer for C2 communication. The attackers have exploited Ivanti Connect Secure zero-day vulnerabilities (CVE-2023-46805 and CVE-2024-21887) for initial access. The attackers have used a custom dropper to install a malicious Java Servlet filter (BRICKSTEAL) in memory, avoiding detection. The attackers have modified init.d, rc.local, or systemd files to ensure persistence on appliances. The attackers have targeted Windows environments in Europe since at least November 2022. The attackers have been linked to other related Chinese threat actors besides UNC5221. The campaign has been monitored by Mandiant since March 2025. The attackers have targeted downstream customers of compromised SaaS providers. The attackers are believed to be analyzing stolen source code to identify zero-day vulnerabilities in enterprise technologies. The attackers use a delay timer to lie dormant on infected systems until a hard-coded date. The malware employs Garble, an open-source tool, for code obfuscation to hide function names, structures, and logic. Brickstorm has been found on VMware vCenter and ESXi hosts, often deployed prior to pivoting to these systems. The attackers use legitimate cloud services like Cloudflare Workers or Heroku for C2 communications. The attackers use dynamic domains like sslip.io or nip.io that point directly to the C2 server’s IP. The attackers favor appliance and management-plane compromise, per-victim obfuscated Go binaries, delayed-start implants, and Web/DoH C2 to preserve stealth. The attackers harvest and use valid high-privilege credentials to appear as routine administrator tasks. The attackers deploy in-memory servlet filters, remove installer artifacts, and embed delayed-start logic to limit forensic traces. The attackers abuse virtualization management capabilities, such as cloning VMs to extract credential stores offline. The attackers deploy an in-memory Java Servlet filter on vCenter to intercept and decode web authentication to harvest high-privilege credentials. The attackers use a SOCKS proxy on compromised appliances to tunnel into internal networks for interactive access and file retrieval.

A malicious npm package named 'fezbox' was discovered using QR codes to fetch and execute cookie-stealing malware. The package, disguised as a utility library, was downloaded at least 327 times before being removed from the npm registry. The malware targets user credentials and employs steganographic techniques to evade detection. The package was found to fetch a JPG image containing a QR code, which then executes a second-stage payload. The QR code is designed to be unusually dense and difficult to read with standard phone cameras, making it harder to detect. The package was published by a Chinese-speaking attacker using the alias 'janedu' and included multiple layers of obfuscation to evade detection. The malware specifically targets cookies to steal usernames and passwords, sending the stolen information via an HTTPS POST request to a command-and-control server. The package was removed and flagged as malware posing a supply-chain risk. The attacker's activity status on the npm registry remains unclear. The package's ReadMe mentioned a QR Code Module, making its existence seem legitimate. The package used reversed strings as an anti-analysis technique. The payload could read a web cookie and extract the username and password if both were present.

SonicWall has released a firmware update to remove rootkit malware from SMA 100 series devices, following a breach that exposed firewall configuration backup files. The breach, caused by brute-force attacks, affected less than 5% of customers and may have exposed sensitive information. SonicWall has advised customers to reset credentials and update secrets. Additionally, the Akira ransomware group has been targeting unpatched SonicWall devices, exploiting a year-old security flaw (CVE-2024-40766) and bypassing MFA on VPN accounts using previously stolen OTP seeds. There is no evidence that threat actors have leveraged exposed data against impacted customers in attacks at this time. In September 2025, SonicWall disclosed a security breach affecting MySonicWall accounts, resulting in the exposure of firewall configuration backup files for less than 5% of its customers. The breach, caused by a series of brute-force attacks, could facilitate easier exploitation of SonicWall firewalls by threat actors. SonicWall has advised customers to reset credentials, update secrets, and follow detailed guidance to mitigate potential risks. The company has cut off attackers' access and is collaborating with cybersecurity and law enforcement agencies. The exposed files may contain sensitive information, such as credentials and tokens, for services running on SonicWall devices. Additionally, the Akira ransomware group has been targeting unpatched SonicWall devices, exploiting a year-old security flaw (CVE-2024-40766) and bypassing MFA on VPN accounts using previously stolen OTP seeds. SonicWall confirmed that attackers accessed the API service for cloud backup and there is no evidence that threat actors have leveraged exposed data against impacted customers in attacks at this time. The threat actor UNC6148 has been deploying the OVERSTEP malware, a previously unknown persistent backdoor/user-mode rootkit, to maintain persistent access, steal sensitive credentials, and conceal its own components. The malware modifies the appliance's boot process to evade detection and hide files and activity. UNC6148 may have used an unknown zero-day remote code execution vulnerability to deploy OVERSTEP on SonicWall SMA appliances. Potential vulnerabilities exploited by UNC6148 include CVE-2021-20038, CVE-2024-38475, CVE-2021-20035, CVE-2021-20039, and CVE-2025-32819. SonicWall has advised customers to look for signs of compromise, such as gaps or deletions in SMA logs, unexpected appliance reboots, persistent admin sessions, unauthorized configuration changes, and reoccurring access following patching or resets. CISA recommends upgrading firmware, replacing and rebuilding SMA 500v, resetting OTP bindings, enforcing MFA, resetting passwords, and replacing certificates with private keys stored on the appliance.