rule win_agent_btz_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.agent_btz." 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.agent_btz" 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 = { c74608ffffffff f644240801 7409 56 e8???????? } // n = 5, score = 2400 // c74608ffffffff | mov dword ptr [esi + 8], 0xffffffff // f644240801 | test byte ptr [esp + 8], 1 // 7409 | je 0xb // 56 | push esi // e8???????? | $sequence_1 = { ffd6 8d54240c 52 ffd7 } // n = 4, score = 2400 // ffd6 | call esi // 8d54240c | lea edx, [esp + 0xc] // 52 | push edx // ffd7 | call edi $sequence_2 = { 8d4c240c 51 ffd6 8d54240c } // n = 4, score = 2400 // 8d4c240c | lea ecx, [esp + 0xc] // 51 | push ecx // ffd6 | call esi // 8d54240c | lea edx, [esp + 0xc] $sequence_3 = { 50 ffd3 85c0 75d8 5f } // n = 5, score = 2400 // 50 | push eax // ffd3 | call ebx // 85c0 | test eax, eax // 75d8 | jne 0xffffffda // 5f | pop edi $sequence_4 = { b805000f00 8b4df4 64890d00000000 5f 5e 5b } // n = 6, score = 2300 // b805000f00 | mov eax, 0xf0005 // 8b4df4 | mov ecx, dword ptr [ebp - 0xc] // 64890d00000000 | mov dword ptr fs:[0], ecx // 5f | pop edi // 5e | pop esi // 5b | pop ebx $sequence_5 = { c7460c00000000 895e08 895e04 c7461000000000 895e14 } // n = 5, score = 2300 // c7460c00000000 | mov dword ptr [esi + 0xc], 0 // 895e08 | mov dword ptr [esi + 8], ebx // 895e04 | mov dword ptr [esi + 4], ebx // c7461000000000 | mov dword ptr [esi + 0x10], 0 // 895e14 | mov dword ptr [esi + 0x14], ebx $sequence_6 = { ff15???????? b803000f00 8b4df4 64890d00000000 } // n = 4, score = 2300 // ff15???????? | // b803000f00 | mov eax, 0xf0003 // 8b4df4 | mov ecx, dword ptr [ebp - 0xc] // 64890d00000000 | mov dword ptr fs:[0], ecx $sequence_7 = { 56 6a00 68???????? 8935???????? } // n = 4, score = 2200 // 56 | push esi // 6a00 | push 0 // 68???????? | // 8935???????? | $sequence_8 = { 8d542408 52 c744240c30000000 c744241003000000 } // n = 4, score = 2100 // 8d542408 | lea edx, [esp + 8] // 52 | push edx // c744240c30000000 | mov dword ptr [esp + 0xc], 0x30 // c744241003000000 | mov dword ptr [esp + 0x10], 3 $sequence_9 = { 83f8ff 740e 50 ff15???????? c74608ffffffff f644240801 } // n = 6, score = 2100 // 83f8ff | cmp eax, -1 // 740e | je 0x10 // 50 | push eax // ff15???????? | // c74608ffffffff | mov dword ptr [esi + 8], 0xffffffff // f644240801 | test byte ptr [esp + 8], 1 $sequence_10 = { 8b4608 c706???????? 85c0 7413 83f8ff 740e } // n = 6, score = 2100 // 8b4608 | mov eax, dword ptr [esi + 8] // c706???????? | // 85c0 | test eax, eax // 7413 | je 0x15 // 83f8ff | cmp eax, -1 // 740e | je 0x10 $sequence_11 = { 51 6a00 6819000200 6a00 68???????? } // n = 5, score = 1400 // 51 | push ecx // 6a00 | push 0 // 6819000200 | push 0x20019 // 6a00 | push 0 // 68???????? | $sequence_12 = { 6a0a 68???????? 6a01 6a00 } // n = 4, score = 1400 // 6a0a | push 0xa // 68???????? | // 6a01 | push 1 // 6a00 | push 0 $sequence_13 = { 6a01 6a04 6a01 68???????? } // n = 4, score = 1100 // 6a01 | push 1 // 6a04 | push 4 // 6a01 | push 1 // 68???????? | $sequence_14 = { 50 68???????? 6a01 68???????? e8???????? 83c410 } // n = 6, score = 1100 // 50 | push eax // 68???????? | // 6a01 | push 1 // 68???????? | // e8???????? | // 83c410 | add esp, 0x10 $sequence_15 = { 50 e8???????? 83c408 6800010000 e8???????? } // n = 5, score = 1000 // 50 | push eax // e8???????? | // 83c408 | add esp, 8 // 6800010000 | push 0x100 // e8???????? | $sequence_16 = { 6a01 68???????? e8???????? 83c414 5f 5e } // n = 6, score = 1000 // 6a01 | push 1 // 68???????? | // e8???????? | // 83c414 | add esp, 0x14 // 5f | pop edi // 5e | pop esi $sequence_17 = { 68???????? 6a01 e8???????? 50 e8???????? 83c41c } // n = 6, score = 900 // 68???????? | // 6a01 | push 1 // e8???????? | // 50 | push eax // e8???????? | // 83c41c | add esp, 0x1c $sequence_18 = { 0fb605???????? 66890d???????? 0fb60d???????? 660fafca 6603c8 } // n = 5, score = 900 // 0fb605???????? | // 66890d???????? | // 0fb60d???????? | // 660fafca | imul cx, dx // 6603c8 | add cx, ax $sequence_19 = { 7511 e8???????? 83c020 50 e8???????? 83c404 } // n = 6, score = 900 // 7511 | jne 0x13 // e8???????? | // 83c020 | add eax, 0x20 // 50 | push eax // e8???????? | // 83c404 | add esp, 4 $sequence_20 = { 89461c 3dea000000 740b 3de5030000 } // n = 4, score = 900 // 89461c | mov ecx, dword ptr [ebp - 0xc] // 3dea000000 | mov dword ptr fs:[0], ecx // 740b | pop edi // 3de5030000 | pop esi $sequence_21 = { c684248800000043 c684248900000072 c684248a00000065 c684248b00000061 c684248c00000074 c684248d00000065 c684248e00000050 } // n = 7, score = 800 // c684248800000043 | mov byte ptr [esp + 0x88], 0x43 // c684248900000072 | mov byte ptr [esp + 0x89], 0x72 // c684248a00000065 | mov byte ptr [esp + 0x8a], 0x65 // c684248b00000061 | mov byte ptr [esp + 0x8b], 0x61 // c684248c00000074 | mov byte ptr [esp + 0x8c], 0x74 // c684248d00000065 | mov byte ptr [esp + 0x8d], 0x65 // c684248e00000050 | mov byte ptr [esp + 0x8e], 0x50 $sequence_22 = { c684249500000057 c684249600000000 c684241001000047 c684241101000065 c684241201000074 } // n = 5, score = 800 // c684249500000057 | mov byte ptr [esp + 0x95], 0x57 // c684249600000000 | mov byte ptr [esp + 0x96], 0 // c684241001000047 | mov byte ptr [esp + 0x110], 0x47 // c684241101000065 | mov byte ptr [esp + 0x111], 0x65 // c684241201000074 | mov byte ptr [esp + 0x112], 0x74 $sequence_23 = { 8d4df8 51 8d8df8f7ffff 51 57 } // n = 5, score = 800 // 8d4df8 | pop edi // 51 | pop esi // 8d8df8f7ffff | mov eax, 0xf0004 // 51 | mov ecx, dword ptr [ebp - 0xc] // 57 | mov dword ptr fs:[0], ecx $sequence_24 = { ff9574ffffff 8b4de0 89410c 33c0 8be5 5d c20400 } // n = 7, score = 800 // ff9574ffffff | call dword ptr [ebp - 0x8c] // 8b4de0 | mov ecx, dword ptr [ebp - 0x20] // 89410c | mov dword ptr [ecx + 0xc], eax // 33c0 | xor eax, eax // 8be5 | mov esp, ebp // 5d | pop ebp // c20400 | ret 4 $sequence_25 = { c684248c00000074 c684248d00000065 c684248e00000050 c684248f00000072 c68424900000006f c684249100000063 c684249200000065 } // n = 7, score = 800 // c684248c00000074 | mov byte ptr [esp + 0x8c], 0x74 // c684248d00000065 | mov byte ptr [esp + 0x8d], 0x65 // c684248e00000050 | mov byte ptr [esp + 0x8e], 0x50 // c684248f00000072 | mov byte ptr [esp + 0x8f], 0x72 // c68424900000006f | mov byte ptr [esp + 0x90], 0x6f // c684249100000063 | mov byte ptr [esp + 0x91], 0x63 // c684249200000065 | mov byte ptr [esp + 0x92], 0x65 $sequence_26 = { 8b4624 6888130000 ff7618 897dfc } // n = 4, score = 800 // 8b4624 | mov ecx, dword ptr [ebp - 0xc] // 6888130000 | mov dword ptr fs:[0], ecx // ff7618 | pop edi // 897dfc | pop esi $sequence_27 = { 8b5d0c 56 8bf0 8b4624 } // n = 4, score = 800 // 8b5d0c | mov eax, 0xf0005 // 56 | mov ecx, dword ptr [ebp - 0xc] // 8bf0 | mov dword ptr fs:[0], ecx // 8b4624 | pop edi $sequence_28 = { 66894dea 59 6a65 668945f0 66894dec } // n = 5, score = 800 // 66894dea | pop edi // 59 | pop esi // 6a65 | mov eax, 0xf0000 // 668945f0 | mov ecx, dword ptr [ebp - 0xc] // 66894dec | mov dword ptr fs:[0], ecx $sequence_29 = { 8bf1 33db 895e10 895e0c } // n = 4, score = 800 // 8bf1 | mov ecx, dword ptr [ebp - 0xc] // 33db | mov dword ptr fs:[0], ecx // 895e10 | mov eax, 0xf0003 // 895e0c | mov ecx, dword ptr [ebp - 0xc] $sequence_30 = { 6a00 6a27 6a02 6a00 6a01 } // n = 5, score = 800 // 6a00 | push 0 // 6a27 | push 0x27 // 6a02 | push 2 // 6a00 | push 0 // 6a01 | push 1 $sequence_31 = { 59 6a25 58 6a30 668945f2 58 6a38 } // n = 7, score = 800 // 59 | mov ecx, dword ptr [ebp - 0xc] // 6a25 | mov dword ptr fs:[0], ecx // 58 | pop edi // 6a30 | pop esi // 668945f2 | pop ebx // 58 | mov eax, 0xf0005 // 6a38 | mov ecx, dword ptr [ebp - 0xc] $sequence_32 = { 037dfc 8b4508 83c414 837df800 8938 } // n = 5, score = 800 // 037dfc | pop esi // 8b4508 | pop ebx // 83c414 | mov eax, 0xf0003 // 837df800 | mov ecx, dword ptr [ebp - 0xc] // 8938 | mov dword ptr fs:[0], ecx $sequence_33 = { c684249100000063 c684249200000065 c684249300000073 c684249400000073 c684249500000057 c684249600000000 } // n = 6, score = 800 // c684249100000063 | mov byte ptr [esp + 0x91], 0x63 // c684249200000065 | mov byte ptr [esp + 0x92], 0x65 // c684249300000073 | mov byte ptr [esp + 0x93], 0x73 // c684249400000073 | mov byte ptr [esp + 0x94], 0x73 // c684249500000057 | mov byte ptr [esp + 0x95], 0x57 // c684249600000000 | mov byte ptr [esp + 0x96], 0 $sequence_34 = { 33c9 ff542458 85c0 7420 } // n = 4, score = 800 // 33c9 | xor ecx, ecx // ff542458 | call dword ptr [esp + 0x58] // 85c0 | test eax, eax // 7420 | je 0x22 $sequence_35 = { 740d 3cff 7409 f6d0 } // n = 4, score = 800 // 740d | je 0xf // 3cff | cmp al, 0xff // 7409 | je 0xb // f6d0 | not al $sequence_36 = { c645d316 c645d43a c645d53b c645d63b c645d730 c645d836 } // n = 6, score = 700 // c645d316 | mov byte ptr [ebp - 0x2d], 0x16 // c645d43a | mov byte ptr [ebp - 0x2c], 0x3a // c645d53b | mov byte ptr [ebp - 0x2b], 0x3b // c645d63b | mov byte ptr [ebp - 0x2a], 0x3b // c645d730 | mov byte ptr [ebp - 0x29], 0x30 // c645d836 | mov byte ptr [ebp - 0x28], 0x36 $sequence_37 = { 8d8505feffff 50 e8???????? 83c40c } // n = 4, score = 700 // 8d8505feffff | lea eax, [ebp - 0x1fb] // 50 | push eax // e8???????? | // 83c40c | add esp, 0xc $sequence_38 = { c645cb30 c645cc27 c645cd3b c645ce30 } // n = 4, score = 700 // c645cb30 | mov byte ptr [ebp - 0x35], 0x30 // c645cc27 | mov byte ptr [ebp - 0x34], 0x27 // c645cd3b | mov byte ptr [ebp - 0x33], 0x3b // c645ce30 | mov byte ptr [ebp - 0x32], 0x30 $sequence_39 = { 488b4338 33d2 488bce 448d4220 } // n = 4, score = 500 // 488b4338 | dec eax // 33d2 | mov eax, dword ptr [ebx + 0x38] // 488bce | xor edx, edx // 448d4220 | dec eax $sequence_40 = { e8???????? 488b5638 488bcf 8bd8 } // n = 4, score = 400 // e8???????? | // 488b5638 | inc ecx // 488bcf | push edi // 8bd8 | dec eax $sequence_41 = { 488b5538 488bce 8bd8 ff92e8010000 } // n = 4, score = 400 // 488b5538 | push ecx // 488bce | lea ecx, [ebp - 0x808] // 8bd8 | push ecx // ff92e8010000 | mov esi, ecx $sequence_42 = { 488b4608 488b0e 48894628 488b4638 4c8d4c2450 } // n = 5, score = 400 // 488b4608 | mov dword ptr fs:[0], ecx // 488b0e | pop edi // 48894628 | pop esi // 488b4638 | pop ebx // 4c8d4c2450 | mov eax, 0xf0004 $sequence_43 = { 4155 4156 4157 4883ec40 488b4138 } // n = 5, score = 400 // 4155 | mov eax, dword ptr [ecx + 8] // 4156 | dec eax // 4157 | mov dword ptr [ecx + 0x28], eax // 4883ec40 | dec eax // 488b4138 | mov ecx, dword ptr [edi] $sequence_44 = { 488b4108 48894128 488b0f 48396928 } // n = 4, score = 400 // 488b4108 | mov eax, dword ptr [edi] // 48894128 | mov dword ptr [eax + 0x30], ebp // 488b0f | xor eax, eax // 48396928 | dec eax $sequence_45 = { 4883ec40 33ed 488bf9 498bf0 } // n = 4, score = 400 // 4883ec40 | dec eax // 33ed | mov ecx, dword ptr [edi] // 488bf9 | dec eax // 498bf0 | mov eax, dword ptr [ecx + 8] $sequence_46 = { 488b0f 894130 eb06 488b07 896830 33c0 488b5c2458 } // n = 7, score = 400 // 488b0f | mov ecx, esi // 894130 | inc esp // eb06 | lea eax, [edx + 0x20] // 488b07 | dec eax // 896830 | mov ecx, dword ptr [edi] // 33c0 | mov dword ptr [ecx + 0x30], eax // 488b5c2458 | jmp 8 $sequence_47 = { 83c904 c1e803 448bc9 440fafc8 } // n = 4, score = 400 // 83c904 | mov eax, 0xf0003 // c1e803 | mov ecx, dword ptr [ebp - 0xc] // 448bc9 | mov dword ptr fs:[0], ecx // 440fafc8 | pop edi $sequence_48 = { 488b0f 488901 488b07 488338ff } // n = 4, score = 400 // 488b0f | mov dword ptr [ecx + 0x28], eax // 488901 | dec eax // 488b07 | mov ecx, dword ptr [edi] // 488338ff | mov dword ptr [ecx + 0x30], eax $sequence_49 = { 488bcf c744242088130000 e8???????? 488b5738 } // n = 4, score = 400 // 488bcf | pop esi // c744242088130000 | pop ebx // e8???????? | // 488b5738 | mov esp, ebp $sequence_50 = { 488b4638 488b0e 4c8d442450 4533c9 } // n = 4, score = 400 // 488b4638 | mov eax, 0xf0003 // 488b0e | mov ecx, dword ptr [ebp - 0xc] // 4c8d442450 | mov dword ptr fs:[0], ecx // 4533c9 | pop edi $sequence_51 = { 488b4638 4c8d4c2450 448bc3 488bd7 } // n = 4, score = 400 // 488b4638 | push ecx // 4c8d4c2450 | mov dword ptr [esi + 0x1c], eax // 448bc3 | cmp eax, 0xea // 488bd7 | je 0x12 $sequence_52 = { 4533c9 488bd6 ff90c8010000 8bf8 } // n = 4, score = 400 // 4533c9 | xor ebx, ebx // 488bd6 | mov dword ptr [esi + 0x10], ebx // ff90c8010000 | mov dword ptr [esi + 0xc], ebx // 8bf8 | mov esi, ecx $sequence_53 = { 488b0f 48894108 488b0f 488b4108 48894128 } // n = 5, score = 400 // 488b0f | dec eax // 48894108 | mov eax, dword ptr [edi] // 488b0f | mov dword ptr [eax + 0x30], ebp // 488b4108 | xor eax, eax // 48894128 | dec eax $sequence_54 = { 8d8594faffff 50 68???????? ff15???????? } // n = 4, score = 300 // 8d8594faffff | lea eax, [ebp - 0x56c] // 50 | push eax // 68???????? | // ff15???????? | $sequence_55 = { 59 5f 5e 5d 5b c3 83ec2c } // n = 7, score = 200 // 59 | pop ecx // 5f | pop edi // 5e | pop esi // 5d | pop ebp // 5b | pop ebx // c3 | ret // 83ec2c | sub esp, 0x2c $sequence_56 = { 8bce 83e11f c1e106 8b0485100b4200 c644080401 } // n = 5, score = 200 // 8bce | mov ecx, esi // 83e11f | and ecx, 0x1f // c1e106 | shl ecx, 6 // 8b0485100b4200 | mov eax, dword ptr [eax*4 + 0x420b10] // c644080401 | mov byte ptr [eax + ecx + 4], 1 $sequence_57 = { 8b1cf56c124200 3bc7 0f851e010000 c745fc00000000 53 } // n = 5, score = 200 // 8b1cf56c124200 | mov ebx, dword ptr [esi*8 + 0x42126c] // 3bc7 | cmp eax, edi // 0f851e010000 | jne 0x124 // c745fc00000000 | mov dword ptr [ebp - 4], 0 // 53 | push ebx $sequence_58 = { 397d00 1bdb 43 742e f7460800000080 } // n = 5, score = 200 // 397d00 | cmp dword ptr [ebp], edi // 1bdb | sbb ebx, ebx // 43 | inc ebx // 742e | je 0x30 // f7460800000080 | test dword ptr [esi + 8], 0x80000000 $sequence_59 = { 8903 85c0 7429 8d4df4 51 8d4dfc 51 } // n = 7, score = 200 // 8903 | mov dword ptr [ebx], eax // 85c0 | test eax, eax // 7429 | je 0x2b // 8d4df4 | lea ecx, [ebp - 0xc] // 51 | push ecx // 8d4dfc | lea ecx, [ebp - 4] // 51 | push ecx $sequence_60 = { ff35???????? 8d047dfeffffff 50 6a01 } // n = 4, score = 200 // ff35???????? | // 8d047dfeffffff | lea eax, [edi*2 - 2] // 50 | push eax // 6a01 | push 1 $sequence_61 = { 5e eb33 53 53 } // n = 4, score = 200 // 5e | pop esi // eb33 | jmp 0x35 // 53 | push ebx // 53 | push ebx condition: 7 of them and filesize < 5577728 }