(YARA) Detect NETReactor Managed Obfuscation

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rule SUSP_OBF_NET_Reactor_Indicators_Jan24
{
	meta:
		description = "Detects indicators of .NET Reactors managed obfuscation. Reactor is a commercial obfuscation solution, pirated versions are often abused by threat actors."
		author = "Jonathan Peters"
		date = "2024-01-09"
		reference = "https://www.eziriz.com/dotnet_reactor.htm"
		hash = "be842a9de19cfbf42ea5a94e3143d58390a1abd1e72ebfec5deeb8107dddf038"
		score = 65
	strings:
		$ = { 33 7B 00 [9] 00 2D 00 [9] 00 2D 00 [9] 00 2D 00 [9] 00 7D 00 }
		$ = { 3C 50 72 69 76 61 74 65 49 6D 70 6C 65 6D 65 6E 74 61 74 69 6F 6E 44 65 74 61 69 6C 73 3E 7B [8] 2D [4] 2D [4] 2D [4] 2D [12] 7D }
		$ = { 3C 4D 6F 64 75 6C 65 3E 7B [8] 2D [4] 2D [4] 2D [4] 2D [12] 7D }
	condition:
      uint16(0) == 0x5a4d
		and 2 of them
}

Associated Techniques

Technique Name Technique ID's Categories Snippet(s)
.Net Reactor U1423

Matching Samples 10 most recent

Sample Name Matching Techniques First Seen Last Seen
Promob5.exe 5 2026-11-10 6 hours, 55 minutes ago
NjRat 0.7D Horror Edition.exe 7 2026-11-05 5 days, 5 hours ago
CustomCurve.dump_Slayed.dll 5 2026-10-16 3 weeks, 4 days ago
chatgpt.exe 8 2026-10-02 1 month, 1 week ago
Promob5.exe 5 2026-09-15 1 month, 3 weeks ago
VehicalLogger.dll 5 2026-04-06 7 months ago
library.dll 8 2026-03-06 8 months ago
DelphinDesktop.dll 8 2026-03-05 8 months ago
DTC22.dll 4 2026-02-11 8 months, 4 weeks ago
UMLoader.dll 7 2026-01-27 9 months, 2 weeks ago
View All

Created

January 10, 2024

Last Revised

March 27, 2026