Ransomware.
rule win_gibberish_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-01-05" version = "1" description = "Detects win.gibberish." 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.gibberish" malpedia_rule_date = "20260105" malpedia_hash = "19b79e7cab4eaf532122e5b45a77dd8f6bb5cc79" malpedia_version = "20251219" 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 = { 894dec 8975e8 668907 894dfc 8bce c745f001000000 8d5102 } // n = 7, score = 100 // 894dec | mov dword ptr [ebp - 0x14], ecx // 8975e8 | mov dword ptr [ebp - 0x18], esi // 668907 | mov word ptr [edi], ax // 894dfc | mov dword ptr [ebp - 4], ecx // 8bce | mov ecx, esi // c745f001000000 | mov dword ptr [ebp - 0x10], 1 // 8d5102 | lea edx, [ecx + 2] $sequence_1 = { 8b74242c 8bd0 8944245c 8bce 8bc6 c1c90b c1c007 } // n = 7, score = 100 // 8b74242c | mov esi, dword ptr [esp + 0x2c] // 8bd0 | mov edx, eax // 8944245c | mov dword ptr [esp + 0x5c], eax // 8bce | mov ecx, esi // 8bc6 | mov eax, esi // c1c90b | ror ecx, 0xb // c1c007 | rol eax, 7 $sequence_2 = { 68???????? ff15???????? 85c0 7424 56 56 8d85fcfffdff } // n = 7, score = 100 // 68???????? | // ff15???????? | // 85c0 | test eax, eax // 7424 | je 0x26 // 56 | push esi // 56 | push esi // 8d85fcfffdff | lea eax, [ebp - 0x20004] $sequence_3 = { 8b0ccdf2a94700 0fb680c8a94500 330cc5f1a94700 8bc2 c1e818 0fb680c8a94500 330cc5f4a94700 } // n = 7, score = 100 // 8b0ccdf2a94700 | mov ecx, dword ptr [ecx*8 + 0x47a9f2] // 0fb680c8a94500 | movzx eax, byte ptr [eax + 0x45a9c8] // 330cc5f1a94700 | xor ecx, dword ptr [eax*8 + 0x47a9f1] // 8bc2 | mov eax, edx // c1e818 | shr eax, 0x18 // 0fb680c8a94500 | movzx eax, byte ptr [eax + 0x45a9c8] // 330cc5f4a94700 | xor ecx, dword ptr [eax*8 + 0x47a9f4] $sequence_4 = { 330a 85d2 894b04 8d4a04 0f44ca } // n = 5, score = 100 // 330a | xor ecx, dword ptr [edx] // 85d2 | test edx, edx // 894b04 | mov dword ptr [ebx + 4], ecx // 8d4a04 | lea ecx, [edx + 4] // 0f44ca | cmove ecx, edx $sequence_5 = { ffd3 8b45d8 8d3446 33c0 83c602 663906 75c3 } // n = 7, score = 100 // ffd3 | call ebx // 8b45d8 | mov eax, dword ptr [ebp - 0x28] // 8d3446 | lea esi, [esi + eax*2] // 33c0 | xor eax, eax // 83c602 | add esi, 2 // 663906 | cmp word ptr [esi], ax // 75c3 | jne 0xffffffc5 $sequence_6 = { f30f7e05???????? 0f114c2420 0f284c2450 660f3840c8 0f10442420 0f11542470 } // n = 6, score = 100 // f30f7e05???????? | // 0f114c2420 | movups xmmword ptr [esp + 0x20], xmm1 // 0f284c2450 | movaps xmm1, xmmword ptr [esp + 0x50] // 660f3840c8 | pmulld xmm1, xmm0 // 0f10442420 | movups xmm0, xmmword ptr [esp + 0x20] // 0f11542470 | movups xmmword ptr [esp + 0x70], xmm2 $sequence_7 = { 7535 017524 297528 2bd6 8b5c242c 5f } // n = 6, score = 100 // 7535 | jne 0x37 // 017524 | add dword ptr [ebp + 0x24], esi // 297528 | sub dword ptr [ebp + 0x28], esi // 2bd6 | sub edx, esi // 8b5c242c | mov ebx, dword ptr [esp + 0x2c] // 5f | pop edi $sequence_8 = { 6af5 eb03 50 6af6 ff15???????? 8b04bd80b64700 } // n = 6, score = 100 // 6af5 | push -0xb // eb03 | jmp 5 // 50 | push eax // 6af6 | push -0xa // ff15???????? | // 8b04bd80b64700 | mov eax, dword ptr [edi*4 + 0x47b680] $sequence_9 = { 33c8 8b44241c 33c6 23442414 33c6 03c8 8b442474 } // n = 7, score = 100 // 33c8 | xor ecx, eax // 8b44241c | mov eax, dword ptr [esp + 0x1c] // 33c6 | xor eax, esi // 23442414 | and eax, dword ptr [esp + 0x14] // 33c6 | xor eax, esi // 03c8 | add ecx, eax // 8b442474 | mov eax, dword ptr [esp + 0x74] condition: 7 of them and filesize < 1068032 }
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