Potential In-Memory Execution Using Reflection.Assembly

calendar Nov 2, 2023 · attack.defense_evasion attack.t1620  ·
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Detects usage of "Reflection.Assembly" load functions to dynamically load assemblies in memory

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 1title: Potential In-Memory Execution Using Reflection.Assembly
 2id: ddcd88cb-7f62-4ce5-86f9-1704190feb0a
 3status: test
 4description: Detects usage of "Reflection.Assembly" load functions to dynamically load assemblies in memory
 5references:
 6    - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=50
 7author: frack113
 8date: 2022/12/25
 9tags:
10    - attack.defense_evasion
11    - attack.t1620
12logsource:
13    product: windows
14    category: ps_script
15    definition: Script Block Logging must be enable
16detection:
17    selection:
18        ScriptBlockText|contains: '[Reflection.Assembly]::load'
19    condition: selection
20falsepositives:
21    - Legitimate use of the library
22level: medium

References

  • Hunting for PowerShell Abuse

    PowerShell is the favorit tool of IT guys, who are responsible for administration of Windows infrastructures. It allows them to manage differen services of the operating system and automate almost anything. But along with administrators, PowerShell also is liked by attackers and malware authors. The reason PowerShell is so attractive for adversaries is quite obvious: it has been included in essentially every Windows operating system by default for a decade, provides access to Windows API, and is rarely constrained, thus allowing adversaries to perform different tasks without risking being blocked. ttackers can use PowerShell to direct the execution of a local script, retrieve and execute remote resources using various network protocols, encode payloads passed via the command line, or load PowerShell into other processes. Because of so prevalence of PowerShell among adversaries for Threat Hunters it is very important to be able to detect malicious uses of PowerShell and defend against it. In the presentation author is going to demostrate an approaches for detection of PowerShell abuses based on different event sources like native Windows logging capabilities as well as usage of additional tools, like Sysmon or EDR solutions. How to collect traces of using PowerShell, how to filter out false positives, and how to find evidence of malicious uses among the remaining after filtering volume of events — all these questions will be answered in the talk for present and future threat hunters.


    Read More

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