Briefs

Adversaries are leveraging legitimate Remote Monitoring and Management (RMM) and remote access tools on Windows endpoints for command-and-control, persistence, and execution, with detection focusing on the first observed instance of these tools on a host.

Threat actors with root privileges can leverage built-in Linux utilities like `insmod` or `modprobe` to load kernel object files, often for installing rootkits that grant complete system control and enable evasion of security products, representing a significant persistence and defense evasion technique.

Adversaries employ Base64 encoding to obfuscate malicious payloads, which are then decoded and executed by interpreters like `bash`, `python`, `perl`, or `ruby` on Linux systems, aiming to evade host- or network-based security controls by piping the output of decoding tools directly to command-line interpreters for arbitrary code execution.

Attackers are actively exploiting Server-Side Request Forgery (SSRF) vulnerabilities in public-facing web applications to access cloud instance metadata services, such as those on AWS, GCP, and Azure, to harvest temporary credentials and sensitive instance details.

This brief describes how to detect an attacker updating or replacing the Sysmon configuration with a bare bones one to avoid monitoring without completely shutting down the service, leveraging Sysmon's `-c` command-line option for defense impairment.

A Missing Authorization vulnerability, identified as CVE-2026-14460, in TUBITAK BILGEM Software Technologies Research Institute's pardus-software versions up to 1.0.4, allows for Argument Injection, posing a high severity risk to confidentiality, integrity, and availability.

This brief details a high-severity Linux privilege escalation technique where an attacker, having gained initial access, drops an exploit in a user- or world-writable directory, executes it as a non-root user, and the resulting child process changes its effective user ID to root (UID 0), thereby achieving full system compromise.

This brief describes a high-severity threat on Linux systems where attackers achieve local privilege escalation by executing a non-root process from a user- or world-writable directory that subsequently gains root privileges (UID 0), indicating a successful exploit to achieve full host compromise.

This brief details a high-severity threat where attackers exploit Linux systems to achieve local privilege escalation by executing a non-root process from a user- or world-writable directory (e.g., /tmp, /dev/shm) that subsequently changes its effective user ID to root (UID 0), indicating a successful abuse of a vulnerable setuid binary or kernel flaw to gain full system control.

Attackers can exploit a Linux kernel vulnerability allowing a process inside a container to modify the `/proc/sys/kernel/core_pattern` file, enabling the execution of arbitrary code as root on the host system upon a core-dump, thereby achieving a full container-to-host escape and privilege escalation.

This brief details the detection of a defense evasion technique where adversaries leverage Busybox on Linux systems to execute commands capable of spawning shells or establishing network connections, thereby attempting to bypass endpoint security controls.

Malware and threat actors on Linux systems utilize the `curl` command to query public web services for external IP address discovery, a reconnaissance technique (T1016) that can precede further C2 establishment or targeted attacks.

This brief identifies suspicious Command and Control (C2) activity on Linux systems where a C2 agent, such as Poseidon or Athena, connects outbound from a sensitive temporary directory and subsequently creates a file in a similar location, indicative of receiving and executing commands from a C2 framework like Mythic.

This brief details a high-severity threat involving the use of `wget.exe` to download suspicious files from known file-sharing domains, a technique observed in campaigns by threat actors such as FIN7 and Mint Sandstorm, enabling initial malware delivery and subsequent system compromise.

This brief details the use of `curl.exe` by an attacker on a compromised Windows host to exfiltrate sensitive data to public file-sharing services, leading to potential data loss and regulatory non-compliance.

A high-severity threat involves the abuse of `curl.exe` on Windows systems to download potentially malicious files from various public file-sharing and content delivery network (CDN) domains, a technique observed in campaigns by threat actors such as FIN7, leading to further system compromise.

This brief details the use of the legitimate Windows utility `certutil.exe` by various threat actors to download malicious files from public file-sharing and code-hosting websites, facilitating further compromise and evasion on targeted systems.

This threat brief details the detection of adversaries leveraging the legitimate Windows Background Intelligent Transfer Service (BITSAdmin) utility to download malicious payloads from suspicious file-sharing and cloud storage domains, a technique commonly employed by ransomware groups and APTs for ingress tool transfer and stealthy execution.

This brief details a detection strategy for suspicious network connections originating from processes located in uncommon or typically protected Windows file system directories, often indicative of malware establishing command and control or exfiltrating data.

This brief details the detection of malicious processes executing from non-standard or temporary Windows directories that initiate network communication with public file-sharing or code repository domains, often indicative of data exfiltration or Command and Control (C2) activities by various threat actors.

This brief details the detection of malicious executables establishing network connections to legitimate popular websites, known as dead drop resolvers, to conduct covert command and control (C2) communications, allowing threat actors to evade traditional security controls and maintain persistent access for data exfiltration or further compromise.

This brief details the detection of suspicious file types (batch, command, PowerShell scripts) downloaded from well-known public file and paste sharing domains, leveraging the `Zone.Identifier` Alternate Data Stream to signal potential malware delivery or covert data transfer, which could lead to system compromise and data exfiltration.

This brief details a high-severity detection aimed at identifying suspicious downloads of executable or script-like files from commonly abused file-sharing and pastebin domains, evidenced by the creation of a 'Zone.Identifier' Alternate Data Stream on Windows systems, a common initial access or payload delivery technique.

Adversaries leverage the Windows Background Intelligent Transfer Service (BITS) to download malicious payloads from legitimate file-sharing and cloud storage domains, enabling stealthy ingress of tools and malware onto compromised systems, a technique observed in campaigns by ransomware groups and nation-state actors.

This brief details the detection of a malicious AppX package downloaded from untrusted file-sharing or CDN domains, a technique employed by threat actors like BazarLoader to deliver malware via abused Windows app mechanisms, potentially leading to system compromise and ransomware.

Threat actors, including those behind IcedID, LockBit, and Vice Society, actively utilize the Windows Management Instrumentation Command-line (WMIC) utility to uninstall or terminate security products, aiming to impair host defenses and facilitate ransomware deployment or data exfiltration.

Adversaries are leveraging the Windows Management Instrumentation Command-line (WMIC) utility, `wmic.exe`, to uninstall legitimate or security applications as a method of defense evasion and system impact within Windows environments.

Adversaries leverage the native Windows Management Instrumentation Command-line (WMIC) utility to terminate applications, specifically security products, as a defense evasion technique.

A high-severity threat involves adversaries abusing `wmic.exe` to create new processes like `rundll32` or `powershell` on Windows systems, a technique observed in ransomware campaigns such as Ryuk, Hive, and Conti, indicating post-compromise execution.

Attackers are leveraging `wmic.exe` to modify the Windows registry through the WMI `StdRegProv` class, specifically using methods like `CreateKey` and `SetStringValue`, to evade detection and bypass traditional security monitoring focused on `reg.exe` or `regedit.exe`.