rule win_gootkit_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.gootkit." 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.gootkit" malpedia_rule_date = "20260916" malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6" malpedia_version = "20260917" 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 = { 8bec 83ec30 53 8bc1 0f57c0 } // n = 5, score = 1700 // 8bec | mov ebp, esp // 83ec30 | sub esp, 0x30 // 53 | push ebx // 8bc1 | mov eax, ecx // 0f57c0 | xorps xmm0, xmm0 $sequence_1 = { 8b470c 894104 8b4d0c 85c9 740a 8b4710 } // n = 6, score = 1700 // 8b470c | mov eax, dword ptr [edi + 0xc] // 894104 | mov dword ptr [ecx + 4], eax // 8b4d0c | mov ecx, dword ptr [ebp + 0xc] // 85c9 | test ecx, ecx // 740a | je 0xc // 8b4710 | mov eax, dword ptr [edi + 0x10] $sequence_2 = { 8b35???????? 81c704010000 6a00 ffd6 50 ff15???????? 8d043f } // n = 7, score = 1700 // 8b35???????? | // 81c704010000 | add edi, 0x104 // 6a00 | push 0 // ffd6 | call esi // 50 | push eax // ff15???????? | // 8d043f | lea eax, [edi + edi] $sequence_3 = { c1cf0d 03f8 41 3bca } // n = 4, score = 1700 // c1cf0d | ror edi, 0xd // 03f8 | add edi, eax // 41 | inc ecx // 3bca | cmp ecx, edx $sequence_4 = { 6a01 6800000080 ff75f4 ff15???????? 8bf8 83ffff 743f } // n = 7, score = 1700 // 6a01 | push 1 // 6800000080 | push 0x80000000 // ff75f4 | push dword ptr [ebp - 0xc] // ff15???????? | // 8bf8 | mov edi, eax // 83ffff | cmp edi, -1 // 743f | je 0x41 $sequence_5 = { 83ffff 743f 6a00 6a00 ff75f8 } // n = 5, score = 1700 // 83ffff | cmp edi, -1 // 743f | je 0x41 // 6a00 | push 0 // 6a00 | push 0 // ff75f8 | push dword ptr [ebp - 8] $sequence_6 = { 8945f8 3b45f0 72d6 eb09 0fb706 8b4dec 8d3c81 } // n = 7, score = 1700 // 8945f8 | mov dword ptr [ebp - 8], eax // 3b45f0 | cmp eax, dword ptr [ebp - 0x10] // 72d6 | jb 0xffffffd8 // eb09 | jmp 0xb // 0fb706 | movzx eax, word ptr [esi] // 8b4dec | mov ecx, dword ptr [ebp - 0x14] // 8d3c81 | lea edi, [ecx + eax*4] $sequence_7 = { 895df8 0fb74314 8d7b18 0fb75b06 } // n = 4, score = 1700 // 895df8 | mov dword ptr [ebp - 8], ebx // 0fb74314 | movzx eax, word ptr [ebx + 0x14] // 8d7b18 | lea edi, [ebx + 0x18] // 0fb75b06 | movzx ebx, word ptr [ebx + 6] $sequence_8 = { 8b7df4 32c0 8b4de4 f3aa } // n = 4, score = 1200 // 8b7df4 | mov edi, dword ptr [ebp - 0xc] // 32c0 | xor al, al // 8b4de4 | mov ecx, dword ptr [ebp - 0x1c] // f3aa | rep stosb byte ptr es:[edi], al $sequence_9 = { f3aa 68???????? ff15???????? 50 } // n = 4, score = 1200 // f3aa | rep stosb byte ptr es:[edi], al // 68???????? | // ff15???????? | // 50 | push eax $sequence_10 = { 50 e8???????? 83c40c 68fd000000 } // n = 4, score = 1100 // 50 | push eax // e8???????? | // 83c40c | add esp, 0xc // 68fd000000 | push 0xfd $sequence_11 = { 50 68???????? ff15???????? 85c0 7505 e8???????? } // n = 6, score = 1100 // 50 | push eax // 68???????? | // ff15???????? | // 85c0 | test eax, eax // 7505 | jne 7 // e8???????? | $sequence_12 = { 50 8b4508 8b00 99 52 } // n = 5, score = 1000 // 50 | push eax // 8b4508 | mov eax, dword ptr [ebp + 8] // 8b00 | mov eax, dword ptr [eax] // 99 | cdq // 52 | push edx $sequence_13 = { 7514 c705????????01000000 c705????????02000000 8be5 5d } // n = 5, score = 900 // 7514 | jne 0x16 // c705????????01000000 | // c705????????02000000 | // 8be5 | mov esp, ebp // 5d | pop ebp $sequence_14 = { 833d????????00 750a 6a32 ff15???????? } // n = 4, score = 800 // 833d????????00 | // 750a | jne 0xc // 6a32 | push 0x32 // ff15???????? | $sequence_15 = { 6808020000 6a00 ff15???????? 50 } // n = 4, score = 800 // 6808020000 | push 0x208 // 6a00 | push 0 // ff15???????? | // 50 | push eax $sequence_16 = { e8???????? 6a0c 6a08 ff15???????? 50 } // n = 5, score = 800 // e8???????? | // 6a0c | push 0xc // 6a08 | push 8 // ff15???????? | // 50 | push eax $sequence_17 = { 6a02 ff15???????? 6888130000 ff15???????? } // n = 4, score = 700 // 6a02 | push 2 // ff15???????? | // 6888130000 | push 0x1388 // ff15???????? | $sequence_18 = { e8???????? 8d45fc 50 6a01 6a01 6a00 } // n = 6, score = 600 // e8???????? | // 8d45fc | lea eax, [ebp - 4] // 50 | push eax // 6a01 | push 1 // 6a01 | push 1 // 6a00 | push 0 $sequence_19 = { e8???????? 85c0 750c c705????????03000000 } // n = 4, score = 500 // e8???????? | // 85c0 | test eax, eax // 750c | jne 0xe // c705????????03000000 | $sequence_20 = { e8???????? 85c0 740d 6810270000 ff15???????? } // n = 5, score = 400 // e8???????? | // 85c0 | test eax, eax // 740d | je 0xf // 6810270000 | push 0x2710 // ff15???????? | $sequence_21 = { 53 53 53 8901 } // n = 4, score = 300 // 53 | push ebx // 53 | push ebx // 53 | push ebx // 8901 | mov dword ptr [ecx], eax $sequence_22 = { 0f110f 0f104820 0f114710 0f104030 0f114f20 0f104840 } // n = 6, score = 200 // 0f110f | movups xmmword ptr [edi], xmm1 // 0f104820 | movups xmm1, xmmword ptr [eax + 0x20] // 0f114710 | movups xmmword ptr [edi + 0x10], xmm0 // 0f104030 | movups xmm0, xmmword ptr [eax + 0x30] // 0f114f20 | movups xmmword ptr [edi + 0x20], xmm1 // 0f104840 | movups xmm1, xmmword ptr [eax + 0x40] $sequence_23 = { 83faff 7508 ff15???????? 8bd0 } // n = 4, score = 200 // 83faff | cmp edx, -1 // 7508 | jne 0xa // ff15???????? | // 8bd0 | mov edx, eax $sequence_24 = { 6a1c 50 56 ff15???????? 8b4de8 b84d5a0000 } // n = 6, score = 200 // 6a1c | push 0x1c // 50 | push eax // 56 | push esi // ff15???????? | // 8b4de8 | mov ecx, dword ptr [ebp - 0x18] // b84d5a0000 | mov eax, 0x5a4d $sequence_25 = { 7412 83ec0c ba???????? b9???????? e8???????? e8???????? } // n = 6, score = 200 // 7412 | je 0x14 // 83ec0c | sub esp, 0xc // ba???????? | // b9???????? | // e8???????? | // e8???????? | $sequence_26 = { 0f104040 0f114740 0f104850 0f114f50 0f104060 0f114760 8b4070 } // n = 7, score = 200 // 0f104040 | movups xmm0, xmmword ptr [eax + 0x40] // 0f114740 | movups xmmword ptr [edi + 0x40], xmm0 // 0f104850 | movups xmm1, xmmword ptr [eax + 0x50] // 0f114f50 | movups xmmword ptr [edi + 0x50], xmm1 // 0f104060 | movups xmm0, xmmword ptr [eax + 0x60] // 0f114760 | movups xmmword ptr [edi + 0x60], xmm0 // 8b4070 | mov eax, dword ptr [eax + 0x70] $sequence_27 = { 663901 754e 8b513c 03d1 813a50450000 } // n = 5, score = 200 // 663901 | cmp word ptr [ecx], ax // 754e | jne 0x50 // 8b513c | mov edx, dword ptr [ecx + 0x3c] // 03d1 | add edx, ecx // 813a50450000 | cmp dword ptr [edx], 0x4550 $sequence_28 = { 750c 807b01ff 7506 807b0225 } // n = 4, score = 200 // 750c | jne 0xe // 807b01ff | cmp byte ptr [ebx + 1], 0xff // 7506 | jne 8 // 807b0225 | cmp byte ptr [ebx + 2], 0x25 $sequence_29 = { b9???????? e8???????? 83ec0c ba???????? b9???????? } // n = 5, score = 200 // b9???????? | // e8???????? | // 83ec0c | sub esp, 0xc // ba???????? | // b9???????? | $sequence_30 = { 0f114760 8b4070 894770 be01000000 } // n = 4, score = 200 // 0f114760 | movups xmmword ptr [edi + 0x60], xmm0 // 8b4070 | mov eax, dword ptr [eax + 0x70] // 894770 | mov dword ptr [edi + 0x70], eax // be01000000 | mov esi, 1 $sequence_31 = { 85c0 7550 ff15???????? 8bf8 893d???????? } // n = 5, score = 200 // 85c0 | test eax, eax // 7550 | jne 0x52 // ff15???????? | // 8bf8 | mov edi, eax // 893d???????? | $sequence_32 = { 7235 8b82dc000000 0382d8000000 03c1 3bd8 } // n = 5, score = 200 // 7235 | jb 0x37 // 8b82dc000000 | mov eax, dword ptr [edx + 0xdc] // 0382d8000000 | add eax, dword ptr [edx + 0xd8] // 03c1 | add eax, ecx // 3bd8 | cmp ebx, eax $sequence_33 = { 8bc8 e8???????? 3935???????? 7412 83ec0c ba???????? } // n = 6, score = 200 // 8bc8 | mov ecx, eax // e8???????? | // 3935???????? | // 7412 | je 0x14 // 83ec0c | sub esp, 0xc // ba???????? | $sequence_34 = { 85c0 7510 8d4864 ff15???????? ffc3 83fb0a 7cd5 } // n = 7, score = 200 // 85c0 | test eax, eax // 7510 | jne 0x12 // 8d4864 | lea ecx, [eax + 0x64] // ff15???????? | // ffc3 | inc ebx // 83fb0a | cmp ebx, 0xa // 7cd5 | jl 0xffffffd7 $sequence_35 = { 8bf9 6a40 6a00 8bf7 57 81e60000ffff e8???????? } // n = 7, score = 200 // 8bf9 | mov edi, ecx // 6a40 | push 0x40 // 6a00 | push 0 // 8bf7 | mov esi, edi // 57 | push edi // 81e60000ffff | and esi, 0xffff0000 // e8???????? | $sequence_36 = { 0f114f20 0f104840 0f114730 0f104050 0f114f40 0f104860 0f114750 } // n = 7, score = 200 // 0f114f20 | movups xmmword ptr [edi + 0x20], xmm1 // 0f104840 | movups xmm1, xmmword ptr [eax + 0x40] // 0f114730 | movups xmmword ptr [edi + 0x30], xmm0 // 0f104050 | movups xmm0, xmmword ptr [eax + 0x50] // 0f114f40 | movups xmmword ptr [edi + 0x40], xmm1 // 0f104860 | movups xmm1, xmmword ptr [eax + 0x60] // 0f114750 | movups xmmword ptr [edi + 0x50], xmm0 condition: 7 of them and filesize < 516096 }