LimeCrypter

Created the Thursday 18 January 2024. Updated 10 months ago.

Limecrypter is a sophisticated obfuscation tool designed for both native and .NET files. It employs a unique approach to secure payloads by encrypting them within a .NET-based stub. This stub acts as a container for the encrypted payload, ensuring its contents remain concealed until execution.

Technique Identifier

U1436

Technique Tags

crypter limecrypter

Detection Rules

rule MAL_NET_LimeCrypter_RunPE_Jan24
{
	meta:
		description = "Detects LimeCrypter RunPE module. LimeCrypter is an open source .NET based crypter and loader commonly used by threat actors"
		author = "Jonathan Peters"
		date = "2024-01-16"
		reference = "https://github.com/NYAN-x-CAT/Lime-Crypter/tree/master"
		hash = "bcc8c679acfc3aabf22ebdb2349b1fabd351a89fd23a716d85154049d352dd12"
		score = 80
	strings:
		$op1 = { 1F 1A 58 1F 1A 58 28 }                                        //  BitConverter.ToInt32(... + 0x2A + 0x2A);
		$op2 = { 20 B3 00 00 00 8D ?? 00 00 01 13 ?? 11 ?? 16 20 02 00 01 00 } // int[] context = new int[0xB3]; context[0] = 0x10002;
		$op3 = { 11 0? 11 0? 20 00 30 00 00 1F 40 28 ?? 00 00 06 }             // VirtualAllocEx( ... 0x3000, 0x40);
		$op4 = { 6E 20 FF 7F 00 00 6A FE 02 }                                  // (ulong)bufferSize > 0x7FFFUL

		$s1 = "RawSecurityDescriptor" ascii
		$s2 = "CommonAce" ascii
	condition:
		uint16(0) == 0x5a4d and
		all of ($s*) and
		2 of ($op*)
}

Contributor

Jonathan Peters

Additional Resources

External Links

The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.