Update Date
10/20/2023

Class: Trojan-ArcBomb

These Trojans are archives designed to freeze or slow performance or to flood the disk with a large amount of “empty” data when an attempt is made to unpack the archived data. So-called archive bombs pose a particular threat for file and mail servers when an automated processing system is used to process incoming data: an archive bomb can simply crash the server. This type of Trojan uses three types of “bomb”: malcrafted archive headers repeating data identical files in the archive. Malcrafted archive headers or corrupted data in an archive can cause a specific packer or unpacking algorithm to crash when processing the archive contents. The large size of files that contain repeating data make it possible to pack the file into a small archive (i.e. 5GB of data can be packed into a 200KB RAR or a 480KB ZIP archive). A large number of identical files in an archive will also have very little impact on the size of the archive when they are packed using special methods (for example, there are ways to pack 10100 identical files into a 30KB RAR or a 230KB ZIP archive).

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Platform:

No platform description

Family: Trojan.Win64.Agent

No family description

Examples

F5C202CC5E0C61ABB7ABBB2BE96AB2A9
50357B5BBAC2A38B08B9E7E5CB1A05CB
03BA7D8E954620E4AF9C7FD543A89E49
3A91206BED6EECA4CF9D27F56FCA4475
2AB376F23D5D4D2886FBC35729FF7385

Tactics and Techniques: Mitre*

TA0002
Execution

An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, and .cpl.


T1204.002
Malicious File

An adversary may rely upon a user opening a malicious file in order to gain execution. Users may be subjected to social engineering to get them to open a file that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Attachment. Adversaries may use several types of files that require a user to execute them, including .doc, .pdf, .xls, .rtf, .scr, .exe, .lnk, .pif, and .cpl.


TA0003
Persistence

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the “run keys” in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account’s associated permissions level.


T1547.001
Registry Run Keys / Startup Folder

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the “run keys” in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account’s associated permissions level.


TA0004
Privilege Escalation

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the “run keys” in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account’s associated permissions level.


T1547.001
Registry Run Keys / Startup Folder

Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the “run keys” in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account’s associated permissions level.


TA0005
Defense Evasion

Adversaries may interact with the Windows Registry to hide configuration information within Registry keys, remove information as part of cleaning up, or as part of other techniques to aid in persistence and execution.


T1112
Modify Registry

Adversaries may interact with the Windows Registry to hide configuration information within Registry keys, remove information as part of cleaning up, or as part of other techniques to aid in persistence and execution.


T1497.001
System Checks

Adversaries may employ various system checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.


TA0007
Discovery

Adversaries may employ various system checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.


T1497.001
System Checks

Adversaries may employ various system checks to detect and avoid virtualization and analysis environments. This may include changing behaviors based on the results of checks for the presence of artifacts indicative of a virtual machine environment (VME) or sandbox. If the adversary detects a VME, they may alter their malware to disengage from the victim or conceal the core functions of the implant. They may also search for VME artifacts before dropping secondary or additional payloads. Adversaries may use the information learned from Virtualization/Sandbox Evasion during automated discovery to shape follow-on behaviors.


* © 2025 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation.

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