Actor(s): Lazarus Group
SHADYCAT is a dropper and spreader component for the HERMES 2.1 RANSOMWARE radical edition.
rule win_bitsran_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-12-06" version = "1" description = "Detects win.bitsran." info = "autogenerated rule brought to you by yara-signator" tool = "yara-signator v0.6.0" signator_config = "callsandjumps;datarefs;binvalue" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.bitsran" malpedia_rule_date = "20231130" malpedia_hash = "fc8a0e9f343f6d6ded9e7df1a64dac0cc68d7351" malpedia_version = "20230808" malpedia_license = "CC BY-SA 4.0" malpedia_sharing = "TLP:WHITE" /* DISCLAIMER * The strings used in this rule have been automatically selected from the * disassembly of memory dumps and unpacked files, using YARA-Signator. * The code and documentation is published here: * https://github.com/fxb-cocacoding/yara-signator * As Malpedia is used as data source, please note that for a given * number of families, only single samples are documented. * This likely impacts the degree of generalization these rules will offer. * Take the described generation method also into consideration when you * apply the rules in your use cases and assign them confidence levels. */ strings: $sequence_0 = { 85c0 7433 56 57 8bbdf8bfffff c1ef02 } // n = 6, score = 100 // 85c0 | test eax, eax // 7433 | je 0x35 // 56 | push esi // 57 | push edi // 8bbdf8bfffff | mov edi, dword ptr [ebp - 0x4008] // c1ef02 | shr edi, 2 $sequence_1 = { 8911 8b0d???????? 8b9d58fdffff eb5e 8b35???????? } // n = 5, score = 100 // 8911 | mov dword ptr [ecx], edx // 8b0d???????? | // 8b9d58fdffff | mov ebx, dword ptr [ebp - 0x2a8] // eb5e | jmp 0x60 // 8b35???????? | $sequence_2 = { 85f6 7417 8b4508 50 } // n = 4, score = 100 // 85f6 | test esi, esi // 7417 | je 0x19 // 8b4508 | mov eax, dword ptr [ebp + 8] // 50 | push eax $sequence_3 = { 50 53 e8???????? 8b9d44fdffff 83ef04 } // n = 5, score = 100 // 50 | push eax // 53 | push ebx // e8???????? | // 8b9d44fdffff | mov ebx, dword ptr [ebp - 0x2bc] // 83ef04 | sub edi, 4 $sequence_4 = { 83c408 85c0 7403 8975fc 8b03 8d55b8 52 } // n = 7, score = 100 // 83c408 | add esp, 8 // 85c0 | test eax, eax // 7403 | je 5 // 8975fc | mov dword ptr [ebp - 4], esi // 8b03 | mov eax, dword ptr [ebx] // 8d55b8 | lea edx, [ebp - 0x48] // 52 | push edx $sequence_5 = { 742b 8bc1 2bc1 c1f802 8d348500000000 } // n = 5, score = 100 // 742b | je 0x2d // 8bc1 | mov eax, ecx // 2bc1 | sub eax, ecx // c1f802 | sar eax, 2 // 8d348500000000 | lea esi, [eax*4] $sequence_6 = { 8b04c5046f4100 5d c3 8bff } // n = 4, score = 100 // 8b04c5046f4100 | mov eax, dword ptr [eax*8 + 0x416f04] // 5d | pop ebp // c3 | ret // 8bff | mov edi, edi $sequence_7 = { 8d95d4fbffff 52 53 ff15???????? 837d1401 7407 } // n = 6, score = 100 // 8d95d4fbffff | lea edx, [ebp - 0x42c] // 52 | push edx // 53 | push ebx // ff15???????? | // 837d1401 | cmp dword ptr [ebp + 0x14], 1 // 7407 | je 9 $sequence_8 = { 2bc3 c1f802 3dfeffff3f 0f87d0010000 8bca 2bcb } // n = 6, score = 100 // 2bc3 | sub eax, ebx // c1f802 | sar eax, 2 // 3dfeffff3f | cmp eax, 0x3ffffffe // 0f87d0010000 | ja 0x1d6 // 8bca | mov ecx, edx // 2bcb | sub ecx, ebx $sequence_9 = { 899d58fdffff 3bd9 0f83fe000000 3bd3 0f87f6000000 8b35???????? 2bda } // n = 7, score = 100 // 899d58fdffff | mov dword ptr [ebp - 0x2a8], ebx // 3bd9 | cmp ebx, ecx // 0f83fe000000 | jae 0x104 // 3bd3 | cmp edx, ebx // 0f87f6000000 | ja 0xfc // 8b35???????? | // 2bda | sub ebx, edx condition: 7 of them and filesize < 344064 }
If your designated proposal does not fit in any other category, feel free to write a free-text in the comment field below. Changes regarding references should be proposed on the Malpedia library page.
Your suggestion will be reviewed before being published. Thank you for contributing!
YYYY-MM-DD
YYYY-MM
YYYY