Actor(s): Lunar Spider
There is no description at this point.
rule win_vawtrak_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2020-05-30" version = "1" description = "autogenerated rule brought to you by yara-signator" tool = "yara-signator v0.4.0" tool_config = "callsandjumps;datarefs;binvalue" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.vawtrak" malpedia_rule_date = "20200529" malpedia_hash = "92c362319514e5a6da26204961446caa3a8b32a8" malpedia_version = "20200529" 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 / approach 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 6a00 6a00 e8???????? 50 ff15???????? } // n = 6, score = 2600 // 50 | push eax // 6a00 | push 0 // 6a00 | push 0 // e8???????? | // 50 | push eax // ff15???????? | $sequence_1 = { ff35???????? 6a04 6a01 50 } // n = 4, score = 2600 // ff35???????? | // 6a04 | push 4 // 6a01 | push 1 // 50 | push eax $sequence_2 = { 74f6 e8???????? 33c9 870e } // n = 4, score = 2400 // 74f6 | je 0xfffffff8 // e8???????? | // 33c9 | xor ecx, ecx // 870e | xchg dword ptr [esi], ecx $sequence_3 = { c3 33c0 b900000080 40 8901 } // n = 5, score = 2400 // c3 | ret // 33c0 | xor eax, eax // b900000080 | mov ecx, 0x80000000 // 40 | inc eax // 8901 | mov dword ptr [ecx], eax $sequence_4 = { f7d8 1bc0 f7d8 eb02 33c0 8be5 } // n = 6, score = 2400 // f7d8 | neg eax // 1bc0 | sbb eax, eax // f7d8 | neg eax // eb02 | jmp 4 // 33c0 | xor eax, eax // 8be5 | mov esp, ebp $sequence_5 = { ba00ff0000 8bc1 23c2 3bc2 } // n = 4, score = 2400 // ba00ff0000 | mov edx, 0xff00 // 8bc1 | mov eax, ecx // 23c2 | and eax, edx // 3bc2 | cmp eax, edx $sequence_6 = { e8???????? 837d1040 752d 8b4d04 e8???????? 85c0 } // n = 6, score = 2400 // e8???????? | // 837d1040 | cmp dword ptr [ebp + 0x10], 0x40 // 752d | jne 0x2f // 8b4d04 | mov ecx, dword ptr [ebp + 4] // e8???????? | // 85c0 | test eax, eax $sequence_7 = { c3 56 be???????? 33c0 } // n = 4, score = 2400 // c3 | ret // 56 | push esi // be???????? | // 33c0 | xor eax, eax $sequence_8 = { a802 7407 e8???????? eb09 a804 } // n = 5, score = 2200 // a802 | test al, 2 // 7407 | je 9 // e8???????? | // eb09 | jmp 0xb // a804 | test al, 4 $sequence_9 = { 85c0 7515 2105???????? c705????????04000000 } // n = 4, score = 2200 // 85c0 | test eax, eax // 7515 | jne 0x17 // 2105???????? | // c705????????04000000 | $sequence_10 = { 803d????????00 7405 e8???????? e8???????? e8???????? e8???????? } // n = 6, score = 2200 // 803d????????00 | // 7405 | je 7 // e8???????? | // e8???????? | // e8???????? | // e8???????? | $sequence_11 = { 69d26d4ec641 81c239300000 2ac2 8801 } // n = 4, score = 2200 // 69d26d4ec641 | imul edx, edx, 0x41c64e6d // 81c239300000 | add edx, 0x3039 // 2ac2 | sub al, dl // 8801 | mov byte ptr [ecx], al $sequence_12 = { a804 7405 e8???????? 803d????????00 } // n = 4, score = 2200 // a804 | test al, 4 // 7405 | je 7 // e8???????? | // 803d????????00 | $sequence_13 = { 750f 33c9 e8???????? 85c0 7404 } // n = 5, score = 2200 // 750f | jne 0x11 // 33c9 | xor ecx, ecx // e8???????? | // 85c0 | test eax, eax // 7404 | je 6 $sequence_14 = { 7516 c705????????02000000 c705????????03000000 eb14 } // n = 4, score = 2200 // 7516 | jne 0x18 // c705????????02000000 | // c705????????03000000 | // eb14 | jmp 0x16 $sequence_15 = { ff15???????? a3???????? 85c0 74e7 } // n = 4, score = 2000 // ff15???????? | // a3???????? | // 85c0 | test eax, eax // 74e7 | je 0xffffffe9 $sequence_16 = { 6a08 68???????? 56 ffd7 85c0 } // n = 5, score = 2000 // 6a08 | push 8 // 68???????? | // 56 | push esi // ffd7 | call edi // 85c0 | test eax, eax $sequence_17 = { 85c0 7528 68???????? ff15???????? 85c0 7504 } // n = 6, score = 2000 // 85c0 | test eax, eax // 7528 | jne 0x2a // 68???????? | // ff15???????? | // 85c0 | test eax, eax // 7504 | jne 6 $sequence_18 = { 59 57 8bf0 ff15???????? 8bc6 } // n = 5, score = 1900 // 59 | pop ecx // 57 | push edi // 8bf0 | mov esi, eax // ff15???????? | // 8bc6 | mov eax, esi $sequence_19 = { e8???????? 33d2 b9ff3f0000 f7f1 } // n = 4, score = 1900 // e8???????? | // 33d2 | xor edx, edx // b9ff3f0000 | mov ecx, 0x3fff // f7f1 | div ecx $sequence_20 = { 8bc6 8703 3bc6 74f8 } // n = 4, score = 1900 // 8bc6 | mov eax, esi // 8703 | xchg dword ptr [ebx], eax // 3bc6 | cmp eax, esi // 74f8 | je 0xfffffffa $sequence_21 = { 3c0f 7705 80ea61 eb0a 8d42bf 3c0f } // n = 6, score = 1700 // 3c0f | cmp al, 0xf // 7705 | ja 7 // 80ea61 | sub dl, 0x61 // eb0a | jmp 0xc // 8d42bf | lea eax, [edx - 0x41] // 3c0f | cmp al, 0xf $sequence_22 = { eb04 8b01 8907 e8???????? } // n = 4, score = 1700 // eb04 | jmp 6 // 8b01 | mov eax, dword ptr [ecx] // 8907 | mov dword ptr [edi], eax // e8???????? | $sequence_23 = { 56 6a04 53 57 } // n = 4, score = 1700 // 56 | push esi // 6a04 | push 4 // 53 | push ebx // 57 | push edi $sequence_24 = { 85c0 7504 33c0 eb52 e8???????? } // n = 5, score = 1200 // 85c0 | test eax, eax // 7504 | jne 6 // 33c0 | xor eax, eax // eb52 | jmp 0x54 // e8???????? | $sequence_25 = { c1e910 e9???????? 8ac1 c1e904 } // n = 4, score = 1200 // c1e910 | shr ecx, 0x10 // e9???????? | // 8ac1 | mov al, cl // c1e904 | shr ecx, 4 $sequence_26 = { ff15???????? 85c0 7904 33c0 eb1e } // n = 5, score = 1200 // ff15???????? | // 85c0 | test eax, eax // 7904 | jns 6 // 33c0 | xor eax, eax // eb1e | jmp 0x20 $sequence_27 = { 8ac8 240f 80e1f0 80c110 32c8 } // n = 5, score = 900 // 8ac8 | mov cl, al // 240f | and al, 0xf // 80e1f0 | and cl, 0xf0 // 80c110 | add cl, 0x10 // 32c8 | xor cl, al $sequence_28 = { f7d8 1bc0 83e002 83c003 } // n = 4, score = 800 // f7d8 | neg eax // 1bc0 | sbb eax, eax // 83e002 | and eax, 2 // 83c003 | add eax, 3 $sequence_29 = { 3c41 7c11 3c46 7f0d } // n = 4, score = 800 // 3c41 | cmp al, 0x41 // 7c11 | jl 0x13 // 3c46 | cmp al, 0x46 // 7f0d | jg 0xf $sequence_30 = { 89442438 488d542440 488bcb e8???????? 85c0 7507 } // n = 6, score = 700 // 89442438 | mov dword ptr [esp + 0x38], eax // 488d542440 | dec eax // 488bcb | lea edx, [esp + 0x40] // e8???????? | // 85c0 | dec eax // 7507 | mov ecx, ebx $sequence_31 = { b801000000 8705???????? 83f801 74f0 488b0d???????? } // n = 5, score = 700 // b801000000 | mov ebx, eax // 8705???????? | // 83f801 | dec eax // 74f0 | mov ecx, dword ptr [esp + 0x58] // 488b0d???????? | $sequence_32 = { c744243c02000000 ff15???????? 8bd8 488b4c2458 ff15???????? } // n = 5, score = 700 // c744243c02000000 | test eax, eax // ff15???????? | // 8bd8 | jne 0xb // 488b4c2458 | mov dword ptr [esp + 0x3c], 2 // ff15???????? | $sequence_33 = { 458d4104 48897c2428 c74424200c001000 ff15???????? } // n = 4, score = 700 // 458d4104 | mov eax, 1 // 48897c2428 | cmp eax, 1 // c74424200c001000 | je 0xfffffff5 // ff15???????? | condition: 7 of them and filesize < 1027072 }
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