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 = "2023-07-11" version = "1" description = "Detects win.vawtrak." 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.vawtrak" malpedia_rule_date = "20230705" malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41" malpedia_version = "20230715" 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 = { 6a01 ff35???????? 6a04 6a01 } // n = 4, score = 2700 // 6a01 | push 1 // ff35???????? | // 6a04 | push 4 // 6a01 | push 1 $sequence_1 = { 6a04 6a01 50 ff15???????? 85c0 } // n = 5, score = 2700 // 6a04 | push 4 // 6a01 | push 1 // 50 | push eax // ff15???????? | // 85c0 | test eax, eax $sequence_2 = { 6a00 6a00 e8???????? 50 ff15???????? } // n = 5, score = 2600 // 6a00 | push 1 // 6a00 | push 4 // e8???????? | // 50 | push 1 // ff15???????? | $sequence_3 = { 40 8901 81e900100000 75f6 } // n = 4, score = 2400 // 40 | push 1 // 8901 | push eax // 81e900100000 | push 4 // 75f6 | push 1 $sequence_4 = { ba00ff0000 8bc1 23c2 3bc2 } // n = 4, score = 2400 // ba00ff0000 | push 0 // 8bc1 | push eax // 23c2 | push eax // 3bc2 | push 0 $sequence_5 = { c3 56 be???????? 33c0 } // n = 4, score = 2400 // c3 | push eax // 56 | test eax, eax // be???????? | // 33c0 | push 4 $sequence_6 = { 56 ff15???????? eb01 47 } // n = 4, score = 2400 // 56 | push eax // ff15???????? | // eb01 | push 4 // 47 | push 1 $sequence_7 = { 85c0 7516 c705????????02000000 c705????????03000000 eb14 c705????????01000000 } // n = 6, score = 2200 // 85c0 | ret // 7516 | push esi // c705????????02000000 | // c705????????03000000 | // eb14 | xor eax, eax // c705????????01000000 | $sequence_8 = { 7515 2105???????? c705????????04000000 e9???????? } // n = 4, score = 2200 // 7515 | sub ecx, 0x1000 // 2105???????? | // c705????????04000000 | // e9???????? | $sequence_9 = { a802 7407 e8???????? eb09 a804 7405 } // n = 6, score = 2200 // a802 | push 0 // 7407 | push eax // e8???????? | // eb09 | push esi // a804 | jmp 3 // 7405 | inc edi $sequence_10 = { ff15???????? a3???????? 85c0 74e7 } // n = 4, score = 2100 // ff15???????? | // a3???????? | // 85c0 | test eax, eax // 74e7 | je 0xffffffe9 $sequence_11 = { 7528 68???????? ff15???????? 85c0 7504 33c0 } // n = 6, score = 2100 // 7528 | jne 0x2a // 68???????? | // ff15???????? | // 85c0 | test eax, eax // 7504 | jne 6 // 33c0 | xor eax, eax $sequence_12 = { 6a08 68???????? 56 ffd7 85c0 } // n = 5, score = 2100 // 6a08 | push 8 // 68???????? | // 56 | push esi // ffd7 | call edi // 85c0 | test eax, eax $sequence_13 = { 59 57 8bf0 ff15???????? 8bc6 } // n = 5, score = 2000 // 59 | pop ecx // 57 | push edi // 8bf0 | mov esi, eax // ff15???????? | // 8bc6 | mov eax, esi $sequence_14 = { e8???????? 33d2 b9ff3f0000 f7f1 } // n = 4, score = 2000 // e8???????? | // 33d2 | xor edx, edx // b9ff3f0000 | mov ecx, 0x3fff // f7f1 | div ecx $sequence_15 = { 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_16 = { 56 6a04 53 57 } // n = 4, score = 1800 // 56 | push esi // 6a04 | push 4 // 53 | push ebx // 57 | push edi $sequence_17 = { 80ea61 eb0a 8d42bf 3c0f } // n = 4, score = 1700 // 80ea61 | jne 0x19 // eb0a | test eax, eax // 8d42bf | jne 0x1a // 3c0f | jmp 0x1a $sequence_18 = { c1e910 e9???????? 8ac1 c1e904 c0e004 } // n = 5, score = 1200 // c1e910 | shr ecx, 0x10 // e9???????? | // 8ac1 | mov al, cl // c1e904 | shr ecx, 4 // c0e004 | shl al, 4 $sequence_19 = { 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_20 = { 3c41 7c11 3c46 7f0d } // n = 4, score = 800 // 3c41 | cmp al, 0x41 // 7c11 | jl 0x13 // 3c46 | cmp al, 0x46 // 7f0d | jg 0xf $sequence_21 = { 2bca 3bcf 7c2e 03fa 4883c602 03ea 03ff } // n = 7, score = 700 // 2bca | dec eax // 3bcf | mov edi, ecx // 7c2e | mov ecx, 0x10 // 03fa | dec eax // 4883c602 | mov esi, eax // 03ea | dec eax // 03ff | mov ebx, eax $sequence_22 = { 488905???????? 4885c0 74dd 488bd3 } // n = 4, score = 700 // 488905???????? | // 4885c0 | sub ecx, edx // 74dd | cmp ecx, edi // 488bd3 | jl 0x32 $sequence_23 = { 4883ec30 488bf9 e8???????? b910000000 488bf0 e8???????? 488bd8 } // n = 7, score = 700 // 4883ec30 | mov ecx, esi // 488bf9 | dec esp // e8???????? | // b910000000 | mov eax, edi // 488bf0 | dec eax // e8???????? | // 488bd8 | sub esp, 0x30 $sequence_24 = { 4885c0 74e3 448bce 4c8bc7 } // n = 4, score = 700 // 4885c0 | dec eax // 74e3 | test eax, eax // 448bce | je 0xffffffe5 // 4c8bc7 | inc esp condition: 7 of them and filesize < 1027072 }
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