Potential Evasion via ASP.NET Compiler


Description

Identifies the execution of the ASPNET Compiler utility to execute cshap code passed via arguments. Adversaries may abuse this utility to run malicious code.

Query · eql

process where event.action == "start" and
 (process.name : "aspnet_compiler.exe" or process.pe.original_file_name : "aspnet_compiler.exe") and
  process.args : "-v" and process.args : "-f" and process.args : "-u" and not process.args : "-d" and
  not process.parent.executable : ("?:\\Program Files (x86)\\Microsoft Visual Studio*", "?:\\Program Files\\Microsoft Visual Studio*")
Raw source Potential Evasion via ASP.NET Compiler · Elastic TOML
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Published by elastic/protections-artifacts ↗, licensed under Elastic License 2.0 ↗. Reproduced here unmodified.
[rule]
description = """
Identifies the execution of the ASPNET Compiler utility to execute cshap code passed via arguments. Adversaries may
abuse this utility to run malicious code.
"""
id = "2aa05bad-c402-4504-9fbe-cc2fb273193a"
license = "Elastic License v2"
name = "Potential Evasion via ASP.NET Compiler"
os_list = ["windows"]
reference = ["https://lolbas-project.github.io/lolbas/Binaries/Aspnet_Compiler/"]
version = "1.0.7"

query = '''
process where event.action == "start" and
 (process.name : "aspnet_compiler.exe" or process.pe.original_file_name : "aspnet_compiler.exe") and
  process.args : "-v" and process.args : "-f" and process.args : "-u" and not process.args : "-d" and
  not process.parent.executable : ("?:\\Program Files (x86)\\Microsoft Visual Studio*", "?:\\Program Files\\Microsoft Visual Studio*")
'''

min_endpoint_version = "7.15.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1218"
name = "System Binary Proxy Execution"
reference = "https://attack.mitre.org/techniques/T1218/"
[[threat.technique.subtechnique]]
id = "T1218.004"
name = "InstallUtil"
reference = "https://attack.mitre.org/techniques/T1218/004/"



[threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"

[internal]
min_endpoint_version = "7.15.0"

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