FISA

Cybersecurity researchers have demonstrated a proof-of-concept (PoC) rootkit dubbed Curing that leverages a Linux asynchronous I/O mechanism called io_uring to bypass traditional system call monitoring. This causes a "major blind spot in Linux runtime security tools," ARMO said. "This mechanism allows a user application to perform various actions without using system calls," the company said in a report shared with The Hacker News. "As a result, security tools relying on system call monitoring are blind' to rootkits working solely on io_uring." io_uring, first introduced in Linux kernel version 5.1 in March 2019, is a Linux kernel system call interface that employs two circular buffers called a submission queue (SQ) and a completion queue (CQ) between the kernel and an application (i.e., user space) to track the submission and completion of I/O requests in an asynchronous manner. The rootkit devised by ARMO facilitates communication betw...

A download manager site served Linux users malware that stealthily stole passwords and other sensitive information for more than three years as part of a supply chain attack. The modus operandi entailed establishing a reverse shell to an actor-controlled server and installing a Bash stealer on the compromised system. The campaign, which took place between 2020 and 2022, is no longer active. "This stealer collects data such as system information, browsing history, saved passwords, cryptocurrency wallet files, as well as credentials for cloud services (AWS, Google Cloud, Oracle Cloud Infrastructure, Azure)," Kaspersky researchers Georgy Kucherin and Leonid Bezvershenko said. The website in question is freedownloadmanager[.]org, which, according to the Russian cybersecurity firm, offers a legitimate Linux software called "Free Download Manager," but starting in January 2020, began redirecting some users who attempted to download it to another domain deb.fdmpkg[.]org th...

A set of memory corruption flaws have been discovered in the  ncurses  (short for new curses) programming library that could be exploited by threat actors to run malicious code on vulnerable Linux and macOS systems. "Using environment variable poisoning, attackers could chain these vulnerabilities to elevate privileges and run code in the targeted program's context or perform other malicious actions," Microsoft Threat Intelligence researchers Jonathan Bar Or, Emanuele Cozzi, and Michael Pearse said in a technical report published today. The vulnerabilities, collectively tracked as  CVE-2023-29491  (CVSS score of 7.8), have been addressed as of April 2023. Microsoft said it also worked with Apple on remediating the macOS-specific issues related to these flaws. Environment variables are user-defined values that can be used by multiple programs on a system and can affect the manner in which they behave on the system. Man...

The threat actors behind the Monti ransomware have resurfaced after a two-month break with a new Linux version of the encryptor in its attacks targeting government and legal sectors. Monti emerged in June 2022, weeks after the Conti ransomware group shut down its operations, deliberately imitating the tactics and tools associated with the latter, including its leaked source code. Not anymore. The new version, per Trend Micro, is a departure of sorts, exhibiting significant changes from its other Linux-based predecessors. "Unlike the earlier variant, which is primarily based on the leaked Conti source code, this new version employs a different encryptor with additional distinct behaviors," Trend Micro researchers Nathaniel Morales and Joshua Paul Ignacio said. A BinDiff analysis has revealed that while the older iterations had a 99% similarity rate with Conti, the latest version has only a 29% similarity rate, suggesting an overhaul. Some of the crucial changes i...