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rule win_microcin_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-12-06" version = "1" description = "Detects win.microcin." 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.microcin" 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 = { 50 56 ff15???????? 85c0 0f45f7 } // n = 5, score = 400 // 50 | mov ecx, dword ptr [ebp - 4] // 56 | mov eax, dword ptr [ebp + 0x10] // ff15???????? | // 85c0 | mov ecx, dword ptr [ebp + ecx*4 - 0x188] // 0f45f7 | mov dword ptr [eax + edx*4], ecx $sequence_1 = { 442bc3 4803d6 4533c9 ff15???????? 85c0 75d9 488b742438 } // n = 7, score = 400 // 442bc3 | lea eax, [ebp - 0x108] // 4803d6 | push 0x104 // 4533c9 | push eax // ff15???????? | // 85c0 | lea eax, [ebp - 0x108] // 75d9 | xor esi, esi // 488b742438 | push eax $sequence_2 = { ff15???????? 488bcb ff15???????? 448bc0 } // n = 4, score = 400 // ff15???????? | // 488bcb | call ebx // ff15???????? | // 448bc0 | test eax, eax $sequence_3 = { 57 4154 4156 4157 488dac2400fbffff 4881ec00060000 488b05???????? } // n = 7, score = 400 // 57 | jle 0x1f // 4154 | cmp byte ptr [ebp + esi - 0x158], 0x3a // 4156 | push 0x10 // 4157 | push eax // 488dac2400fbffff | push esi // 4881ec00060000 | test eax, eax // 488b05???????? | $sequence_4 = { e8???????? 83c40c 8d85f8feffff 6804010000 50 ff15???????? 8d85f8feffff } // n = 7, score = 400 // e8???????? | // 83c40c | push ebx // 8d85f8feffff | dec eax // 6804010000 | sub esp, 0x20 // 50 | mov ebx, ecx // ff15???????? | // 8d85f8feffff | mov ecx, ebx $sequence_5 = { 488b09 418bf8 488bf2 33db } // n = 4, score = 400 // 488b09 | cmovne esi, edi // 418bf8 | push eax // 488bf2 | push 0x1005 // 33db | push 0xffff $sequence_6 = { ff15???????? 8b3d???????? 8d85e0feffff 50 } // n = 4, score = 400 // ff15???????? | // 8b3d???????? | // 8d85e0feffff | jmp 0xffffffd4 // 50 | mov ebx, dword ptr [ebp - 0x30] $sequence_7 = { 488bcb 664489642438 488bf0 ff15???????? } // n = 4, score = 400 // 488bcb | add esp, 0xc // 664489642438 | mov eax, edi // 488bf0 | lea eax, [ebp - 0x108] // ff15???????? | $sequence_8 = { 68ffff0000 56 8b35???????? ffd6 } // n = 4, score = 400 // 68ffff0000 | add esp, 0xc // 56 | lea eax, [ebp - 0x108] // 8b35???????? | // ffd6 | push 0x104 $sequence_9 = { 85c0 7e18 80bc35a8feffff3a 741f 8d85a8feffff 46 50 } // n = 7, score = 400 // 85c0 | inc ecx // 7e18 | mov eax, 0x12010 // 80bc35a8feffff3a | dec eax // 741f | mov ecx, ebp // 8d85a8feffff | inc ecx // 46 | lea edx, [eax + 1] // 50 | inc eax $sequence_10 = { c6840d8002000033 488d8d80020000 ff15???????? 4863c8 c6840d8002000079 } // n = 5, score = 400 // c6840d8002000033 | push esi // 488d8d80020000 | call esi // ff15???????? | // 4863c8 | push 4 // c6840d8002000079 | push dword ptr [ebp - 0x2c] $sequence_11 = { ff15???????? 8b1d???????? 8d85a8feffff 50 ffd3 } // n = 5, score = 400 // ff15???????? | // 8b1d???????? | // 8d85a8feffff | push 0xa400 // 50 | push 0 // ffd3 | mov ecx, dword ptr [ebp - 0x10] $sequence_12 = { ff15???????? 4863c8 c6840d7002000062 488d8d70020000 ff15???????? 4863c8 } // n = 6, score = 400 // ff15???????? | // 4863c8 | test eax, eax // c6840d7002000062 | jle 0x1f // 488d8d70020000 | cmp byte ptr [ebp + esi - 0x158], 0x3a // ff15???????? | // 4863c8 | je 0x30 $sequence_13 = { ff15???????? 85c0 7426 8b400c } // n = 4, score = 400 // ff15???????? | // 85c0 | test eax, eax // 7426 | jle 0x1c // 8b400c | cmp byte ptr [ebp + esi - 0x158], 0x3a $sequence_14 = { 33f6 50 ffd3 85c0 7e18 } // n = 5, score = 400 // 33f6 | sub esp, 8 // 50 | mov dword ptr [ebp - 8], ecx // ffd3 | mov dword ptr [ebp - 4], 0xa400 // 85c0 | push 0x40 // 7e18 | push 0x1000 $sequence_15 = { 488d4c2460 ff15???????? 4863c8 807c0c5f5c 7413 488d4c2460 ff15???????? } // n = 7, score = 400 // 488d4c2460 | push esi // ff15???????? | // 4863c8 | lea eax, [ebp - 0x158] // 807c0c5f5c | push eax // 7413 | call ebx // 488d4c2460 | lea eax, [ebp - 0x108] // ff15???????? | $sequence_16 = { 41bc14030000 4c8d0574130100 488bcd 418bd4 e8???????? 33c9 85c0 } // n = 7, score = 200 // 41bc14030000 | xor eax, eax // 4c8d0574130100 | jbe 0x4c // 488bcd | dec ecx // 418bd4 | mov ecx, ebp // e8???????? | // 33c9 | dec esp // 85c0 | lea eax, [0x112b7] $sequence_17 = { 83c108 51 ff15???????? 8b4dfc } // n = 4, score = 200 // 83c108 | dec ecx // 51 | mov eax, ebx // ff15???????? | // 8b4dfc | dec ecx $sequence_18 = { 7370 696465726167656e 742e 657865 } // n = 4, score = 200 // 7370 | dec esp // 696465726167656e | lea eax, [0x1126c] // 742e | dec eax // 657865 | lea edx, [0x10c73] $sequence_19 = { 6e 6d 656e 7400 } // n = 4, score = 200 // 6e | test eax, eax // 6d | mov ebx, ecx // 656e | dec eax // 7400 | lea ecx, [0x10c95] $sequence_20 = { 8b4510 8b8c8d78feffff 890c90 ebc8 e9???????? } // n = 5, score = 200 // 8b4510 | mov ecx, esi // 8b8c8d78feffff | call eax // 890c90 | mov dword ptr [ebp + 0x118], eax // ebc8 | sub esp, 8 // e9???????? | $sequence_21 = { 7647 498bcd e8???????? 4c8d05b7120100 41b903000000 } // n = 5, score = 200 // 7647 | jne 0x48 // 498bcd | dec esp // e8???????? | // 4c8d05b7120100 | mov eax, ebx // 41b903000000 | dec eax $sequence_22 = { fa fa fa fa fa fa } // n = 6, score = 200 // fa | dec eax // fa | sub esp, 0x20 // fa | mov ebx, ecx // fa | dec eax // fa | lea ecx, [0x10c95] // fa | dec eax $sequence_23 = { 8b4df0 e8???????? 8d45f8 50 6a00 } // n = 5, score = 200 // 8b4df0 | cli // e8???????? | // 8d45f8 | outsb dx, byte ptr [esi] // 50 | insd dword ptr es:[edi], dx // 6a00 | outsb dx, byte ptr gs:[esi] $sequence_24 = { 6828010000 8d85ccfeffff 6a00 50 } // n = 4, score = 200 // 6828010000 | push ebx // 8d85ccfeffff | push ebx // 6a00 | push esi // 50 | inc ebx $sequence_25 = { 418d7c24e7 85c0 752a 4c8d0502130100 8bd7 498bcd } // n = 6, score = 200 // 418d7c24e7 | inc ecx // 85c0 | mov ecx, 3 // 752a | jbe 0x49 // 4c8d0502130100 | dec ecx // 8bd7 | mov ecx, ebp // 498bcd | dec esp $sequence_26 = { 4c8d056c120100 498bd4 488bcd e8???????? 85c0 7541 4c8bc3 } // n = 7, score = 200 // 4c8d056c120100 | dec eax // 498bd4 | lea edx, [0x10c73] // 488bcd | dec eax // e8???????? | // 85c0 | mov ecx, eax // 7541 | dec esp // 4c8bc3 | lea eax, [0x1126c] $sequence_27 = { 636373 7673 6873742e65 7865 } // n = 4, score = 200 // 636373 | cli // 7673 | cli // 6873742e65 | jbe 0x6f // 7865 | jb 0x71 $sequence_28 = { ff15???????? 8b45f4 8b4824 894dfc 8b55f4 83c208 } // n = 6, score = 200 // ff15???????? | // 8b45f4 | inc ebp // 8b4824 | sub ebx, dword ptr [ecx + esi - 0x2008] // 894dfc | inc ebp // 8b55f4 | mov dword ptr [esp + 4], ebx // 83c208 | mov ecx, esi $sequence_29 = { 8945fc eb42 8b45f8 33d2 } // n = 4, score = 200 // 8945fc | je 0xa // eb42 | mov eax, dword ptr [ecx + esi - 0x200c] // 8b45f8 | inc esp // 33d2 | sub ebx, eax $sequence_30 = { 8bd9 488d0d950c0100 ff15???????? 4885c0 7419 488d15730c0100 488bc8 } // n = 7, score = 200 // 8bd9 | mov ebx, ecx // 488d0d950c0100 | dec eax // ff15???????? | // 4885c0 | lea ecx, [0x10c95] // 7419 | dec eax // 488d15730c0100 | test eax, eax // 488bc8 | je 0x1b $sequence_31 = { 488d15f8110100 41b810200100 488bcd e8???????? e9???????? 4533c9 4533c0 } // n = 7, score = 200 // 488d15f8110100 | dec ecx // 41b810200100 | mov edx, esp // 488bcd | dec eax // e8???????? | // e9???????? | // 4533c9 | mov ecx, ebp // 4533c0 | test eax, eax $sequence_32 = { 8b8504ffffff 898574feffff 8b4d0c 8b91fc020000 8b4508 0390f0040000 8b4d10 } // n = 7, score = 200 // 8b8504ffffff | je 5 // 898574feffff | outsb dx, byte ptr [esi] // 8b4d0c | jbe 0x6b // 8b91fc020000 | jb 0x73 // 8b4508 | outsb dx, byte ptr [esi] // 0390f0040000 | insd dword ptr es:[edi], dx // 8b4d10 | outsb dx, byte ptr gs:[esi] $sequence_33 = { 488bcd e8???????? 85c0 751a 488d15f8110100 41b810200100 } // n = 6, score = 200 // 488bcd | dec eax // e8???????? | // 85c0 | mov ecx, ebp // 751a | inc ebp // 488d15f8110100 | xor ecx, ecx // 41b810200100 | inc ebp $sequence_34 = { 8b55fc 83c208 52 ff15???????? 8b45fc c7400421000000 } // n = 6, score = 200 // 8b55fc | dec eax // 83c208 | lea edx, [ebp + 0x10] // 52 | nop // ff15???????? | // 8b45fc | mov edx, 0xc4b3c4b3 // c7400421000000 | mov ecx, dword ptr [esp + 8] $sequence_35 = { 33c9 4889742420 e8???????? cc 4c8d056c120100 } // n = 5, score = 200 // 33c9 | inc ecx // 4889742420 | lea edi, [esp - 0x19] // e8???????? | // cc | test eax, eax // 4c8d056c120100 | jne 0x2c $sequence_36 = { 83ec08 894df8 c745fc00a40000 6a40 6800100000 6800a40000 6a00 } // n = 7, score = 200 // 83ec08 | cli // 894df8 | cli // c745fc00a40000 | cli // 6a40 | cli // 6800100000 | cli // 6800a40000 | cli // 6a00 | cli $sequence_37 = { 49 53 53 56 43 } // n = 5, score = 200 // 49 | test eax, eax // 53 | jne 0x124 // 53 | dec esp // 56 | lea eax, [0x1126c] // 43 | dec ecx $sequence_38 = { 8b4c2414 33cc e8???????? 8be5 5d c21000 57 } // n = 7, score = 100 // 8b4c2414 | xor edx, edx // 33cc | mov ecx, 4 // e8???????? | // 8be5 | div ecx // 5d | add ecx, 8 // c21000 | push ecx // 57 | mov ecx, dword ptr [ebp - 4] $sequence_39 = { 0115???????? 1515151503 1515151515 1515041515 1515050607 0809 } // n = 6, score = 100 // 0115???????? | // 1515151503 | mov eax, dword ptr [ebp - 4] // 1515151515 | mov dword ptr [eax + 4], 0x21 // 1515041515 | mov dword ptr [ebp - 4], eax // 1515050607 | jmp 0x44 // 0809 | mov eax, dword ptr [ebp - 8] $sequence_40 = { 8d85e8feffff 50 ff95e4feffff 59 59 837d1c00 7513 } // n = 7, score = 100 // 8d85e8feffff | insd dword ptr es:[edi], dx // 50 | outsb dx, byte ptr gs:[esi] // ff95e4feffff | je 8 // 59 | jae 0x72 // 59 | imul esp, dword ptr [ebp + 0x72], 0x6e656761 // 837d1c00 | je 0x3a // 7513 | js 0x74 $sequence_41 = { 8b8431f4dfffff 44 2bd8 45 2b9c31f8dfffff 45 895c2404 } // n = 7, score = 100 // 8b8431f4dfffff | push esi // 44 | inc ebx // 2bd8 | jae 0x72 // 45 | imul esp, dword ptr [ebp + 0x72], 0x6e656761 // 2b9c31f8dfffff | je 0x38 // 45 | js 0x72 // 895c2404 | jbe 0x6b $sequence_42 = { 6a00 8d442448 50 ff15???????? 85c0 7420 } // n = 6, score = 100 // 6a00 | add edx, dword ptr [eax + 0x4f0] // 8d442448 | mov ecx, dword ptr [ebp + 0x10] // 50 | mov dword ptr [ebp - 4], eax // ff15???????? | // 85c0 | jmp 0x47 // 7420 | mov eax, dword ptr [ebp - 8] $sequence_43 = { 8b4c2408 49 8b542410 e8???????? 85c0 74db 89c0 } // n = 7, score = 100 // 8b4c2408 | cli // 49 | cli // 8b542410 | cli // e8???????? | // 85c0 | cli // 74db | cli // 89c0 | cli $sequence_44 = { f7f7 8365ec00 85c0 0f8e94010000 8365f000 8b7e44 } // n = 6, score = 100 // f7f7 | push ebx // 8365ec00 | push ebx // 85c0 | push esi // 0f8e94010000 | inc ebx // 8365f000 | jb 0x71 // 8b7e44 | outsb dx, byte ptr [esi] $sequence_45 = { 89f1 48 8d5510 e8???????? 90 e8???????? bab3c4b3c4 } // n = 7, score = 100 // 89f1 | jb 0x71 // 48 | outsb dx, byte ptr [esi] // 8d5510 | insd dword ptr es:[edi], dx // e8???????? | // 90 | outsb dx, byte ptr gs:[esi] // e8???????? | // bab3c4b3c4 | je 8 $sequence_46 = { 6a00 8d85b0feffff 50 56 } // n = 4, score = 100 // 6a00 | mov dword ptr [ebp - 0x18c], eax // 8d85b0feffff | mov ecx, dword ptr [ebp + 0xc] // 50 | mov edx, dword ptr [ecx + 0x2fc] // 56 | mov eax, dword ptr [ebp + 8] $sequence_47 = { 6a00 56 c785b4feffff00000000 ff15???????? 50 56 } // n = 6, score = 100 // 6a00 | xor edx, edx // 56 | mov eax, dword ptr [ebp - 0xc] // c785b4feffff00000000 | mov ecx, dword ptr [eax + 0x24] // ff15???????? | // 50 | mov dword ptr [ebp - 4], ecx // 56 | mov edx, dword ptr [ebp - 0xc] $sequence_48 = { 8d44245c 50 ff15???????? 33c0 5f } // n = 5, score = 100 // 8d44245c | add edx, 8 // 50 | mov edx, dword ptr [ebp - 4] // ff15???????? | // 33c0 | add edx, 8 // 5f | push edx $sequence_49 = { c744241030000000 c744241403000000 c7442418d0114000 c744241c00000000 c744242000000000 89742424 c744242800000000 } // n = 7, score = 100 // c744241030000000 | mov eax, dword ptr [ebp + 0x10] // c744241403000000 | mov ecx, dword ptr [ebp + ecx*4 - 0x188] // c7442418d0114000 | mov dword ptr [eax + edx*4], ecx // c744241c00000000 | jmp 0xffffffd4 // c744242000000000 | mov ebx, dword ptr [ebp - 0x30] // 89742424 | jmp 0xffffffad // c744242800000000 | mov dword ptr [ebp - 0x1c], 0x4060f0 condition: 7 of them and filesize < 417792 }
import "pe" rule win_microcin_w0 { meta: description = "Malware sample mentioned in Microcin technical report by Kaspersky" author = "Florian Roth" reference = "https://securelist.com/files/2017/09/Microcin_Technical-PDF_eng_final.pdf" date = "2017-09-26" hash = "49816eefcd341d7a9c1715e1f89143862d4775ba4f9730397a1e8529f5f5e200" hash = "a73f8f76a30ad5ab03dd503cc63de3a150e6ab75440c1060d75addceb4270f46" hash = "9dd9bb13c2698159eb78a0ecb4e8692fd96ca4ecb50eef194fa7479cb65efb7c" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.microcin" malpedia_version = "20170413" malpedia_license = "CC BY-NC-SA 4.0" malpedia_sharing = "TLP:WHITE" strings: $s1 = "e Class Descriptor at (" fullword ascii $s2 = ".?AVCAntiAntiAppleFrameRealClass@@" fullword ascii $s3 = ".?AVCAntiAntiAppleFrameBaseClass@@" fullword ascii $s4 = ".?AVCAppleBinRealClass@@" fullword ascii $s5 = ".?AVCAppleBinBaseClass@@" fullword ascii condition: uint16(0) == 0x5a4d and filesize < 300KB and (4 of them or pe.imphash() == "897077ca318eaf629cfe74569f10e023") }
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