Bisonal

The attacks use phishing emails to deliver Office documents to exploit targets in order to deliver their RAT of choice, most commonly Bisonal.

admin@338 has attempted to get victims to launch malicious Microsoft Word attachments delivered via spearphishing emails... APT28 attempted to get users to click on Microsoft Office attachments containing malicious macro scripts... Dragonfly has used various forms of spearphishing in attempts to get users to open malicious attachments.

CERT-UA assessed that the documents... were likely built with the Royal Road builder and dropped the Bisonal backdoor.

During the 2016 Ukraine Electric Power Attack, Sandworm Team used the xp_cmdshell command in MS-SQL. During the 2025 Poland Wiper Attacks, the adversaries leveraged PsExec to run cmd.exe commands on multiple victim machines. Numerous malware families and groups are described as using cmd.exe, cmd /c, Windows command shell, or command-line interfaces to execute commands, payloads, reconnaissance, persistence, cleanup, and ransomware actions.

The example documents shown above both exploit CVE-2018-0798, a remote execution vulnerability in Microsoft Office to install the embedded malware.

The content repeatedly describes victims being lured into opening malicious attachments, enabling macros, launching installers, clicking embedded files/links, or otherwise directly executing malicious content.

Sandworm Team leveraged Microsoft Office attachments which contained malicious macros that were automatically executed once the user permitted them... APT29 has used various forms of spearphishing attempting to get a user to open attachments... DarkGate is distributed through phishing links to VBS or MSI objects requiring user interaction for execution.

The content repeatedly describes threat actors and malware modifying, creating, deleting, or storing data in Windows Registry keys and values for persistence, configuration storage, defense evasion, credential access, privilege escalation, and execution.

During the 2016 Ukraine Electric Power Attack, Sandworm Team used an arbitrary system service to load at system boot for persistence for Industroyer. They also replaced the ImagePath registry value of a Windows service with a new backdoor binary.

The content repeatedly describes malware and threat actors establishing persistence by adding values under HKCU/HKLM\Software\Microsoft\Windows\CurrentVersion\Run or RunOnce, and by placing executables, scripts, .lnk files, or .bat files in the Windows Startup folder.

During the 2016 Ukraine Electric Power Attack, Sandworm Team used an arbitrary system service to load at system boot for persistence for Industroyer. They also replaced the ImagePath registry value of a Windows service with a new backdoor binary.

The content repeatedly describes malware and threat actors establishing persistence by adding values under HKCU/HKLM\Software\Microsoft\Windows\CurrentVersion\Run or RunOnce, and by placing executables, scripts, .lnk files, or .bat files in the Windows Startup folder.

The content repeatedly describes payloads, strings, configuration files, scripts, URLs, and binaries being obfuscated or encoded using Base64, XOR, RC4, AES, RSA, hex encoding, custom algorithms, and other methods across many malware families and threat actors.

Examples throughout the content include 'encrypted payloads decrypted and executed in memory,' 'encrypts its configuration file,' 'AES-encrypted resource,' 'RC4 encrypted embedded scripts,' and 'payload includes an encrypted main component.'

During the 2016 Ukraine Electric Power Attack, DLLs and EXEs with filenames associated with common electric power sector protocols were used to masquerade files.

Akira has used legitimate names and locations for files to evade defenses.

Bisonal has deleted Registry keys to clean up its prior activity. FIN8 has deleted Registry keys during post compromise cleanup activities. SUNBURST also deleted previously-created Image File Execution Options (IFEO) Debugger registry values and registry keys related to HTTP proxy to clean up traces of its activity.

The content repeatedly describes threat actors and malware deleting files, tools, scripts, logs, droppers, staged data, and artifacts from compromised systems to cover tracks, remove evidence, or self-delete.

The content repeatedly describes malware and threat actors decoding, decrypting, deobfuscating, or unpacking payloads, strings, configuration data, commands, and C2 responses prior to execution or use.

Agent Tesla has the ability to perform anti-sandboxing and anti-virtualization checks. Bisonal can check to determine if the compromised system is running on VMware. Bumblebee has the ability to perform anti-virtualization checks. CozyCar will check to ensure it is not being executed inside a virtual machine or a known malware analysis sandbox environment. Metamorfo has embedded a "vmdetect.exe" executable to identify virtual machines at the beginning of execution. RTM can detect if it is running within a sandbox or other virtualized analysis environment. Saint Bear contains several anti-analysis and anti-virtualization checks.

The content repeatedly describes threat actors and malware modifying, creating, deleting, or storing data in Windows Registry keys and values for persistence, configuration storage, defense evasion, credential access, privilege escalation, and execution.

The content repeatedly describes malware and threat actors querying, enumerating, searching, reading, or checking Windows Registry keys and values, e.g., "ADVSTORESHELL can enumerate registry keys," "APT41 queried registry values to determine items such as configured RDP ports and network configurations," and "Reg may be used to gather details from the Windows Registry of a local or remote system at the command-line interface."

The content repeatedly describes malware and threat actors using commands and APIs such as ipconfig /all, ifconfig, arp -a, route print, nbtstat, netsh, GetAdaptersInfo, and GetIpNetTable to gather IP addresses, MAC addresses, DNS, DHCP, gateways, routing tables, ARP cache, proxy settings, domains, and network adapter/interface details.

The content repeatedly describes malware and threat actors obtaining lists of running processes, using utilities such as tasklist, ps, WMI, Get-Process, CreateToolhelp32Snapshot, EnumProcesses, and similar APIs/commands to enumerate active processes on victim systems.

The content repeatedly describes malware and threat actors collecting host details such as OS version, hostname, architecture, CPU, memory, BIOS, domain, language, and other configuration data; e.g., "APT41 uses multiple built-in commands such as systeminfo and net config Workstation to enumerate victim system basic configuration information."

The content repeatedly describes malware and threat actors listing files and directories, enumerating drives, searching for files by extension/name/path, retrieving file metadata, and browsing file systems (for example: "APT28 has used Forfiles to locate PDF, Excel, and Word documents during collection" and "cmd can be used to find files and directories with native functionality such as dir commands").

Agent Tesla has the ability to perform anti-sandboxing and anti-virtualization checks. Bisonal can check to determine if the compromised system is running on VMware. Bumblebee has the ability to perform anti-virtualization checks. CozyCar will check to ensure it is not being executed inside a virtual machine or a known malware analysis sandbox environment. Metamorfo has embedded a "vmdetect.exe" executable to identify virtual machines at the beginning of execution. RTM can detect if it is running within a sandbox or other virtualized analysis environment. Saint Bear contains several anti-analysis and anti-virtualization checks.

The content repeatedly describes threat actors and malware collecting, stealing, identifying, copying, or staging files, documents, credentials, logs, databases, and other information from compromised hosts or local systems.

This email contains the Royal Road attachment “Please help to Check.doc” ... and beaconing outbound to instructor.giize[.]com (198.13.56[.]122).

The content repeatedly describes threat actors and malware using HTTP and HTTPS for command and control, such as: "Sandworm Team used BlackEnergy to communicate between compromised hosts and their command-and-control servers via HTTP post requests."

C2 traffic from ADVSTORESHELL is encrypted, then encoded with Base64 encoding... APT19 HTTP malware variant used Base64 to encode communications to the C2 server... APT33 has used base64 to encode command and control traffic.

Bisonal has a uniquely long history of use and continued development by its creators, such as expanding features for file searching and exfiltration...