Actor(s): Oktropys
Ransomware
rule win_aurora_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2022-04-08" version = "1" description = "Detects win.aurora." 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.aurora" malpedia_rule_date = "20220405" malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a" malpedia_version = "20220411" 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 = { 8b4e14 8945d4 8b4610 3bc1 7530 40 83f8fe } // n = 7, score = 300 // 8b4e14 | mov ecx, dword ptr [esi + 0x14] // 8945d4 | mov dword ptr [ebp - 0x2c], eax // 8b4610 | mov eax, dword ptr [esi + 0x10] // 3bc1 | cmp eax, ecx // 7530 | jne 0x32 // 40 | inc eax // 83f8fe | cmp eax, -2 $sequence_1 = { 0fb60431 41 33c2 69d093010001 3bcf 72ef 8bb570ffffff } // n = 7, score = 300 // 0fb60431 | movzx eax, byte ptr [ecx + esi] // 41 | inc ecx // 33c2 | xor eax, edx // 69d093010001 | imul edx, eax, 0x1000193 // 3bcf | cmp ecx, edi // 72ef | jb 0xfffffff1 // 8bb570ffffff | mov esi, dword ptr [ebp - 0x90] $sequence_2 = { 6a00 50 8bf2 e8???????? 68???????? } // n = 5, score = 300 // 6a00 | push 0 // 50 | push eax // 8bf2 | mov esi, edx // e8???????? | // 68???????? | $sequence_3 = { 8d4da8 e8???????? b001 8b4df4 64890d00000000 59 8b4df0 } // n = 7, score = 300 // 8d4da8 | lea ecx, dword ptr [ebp - 0x58] // e8???????? | // b001 | mov al, 1 // 8b4df4 | mov ecx, dword ptr [ebp - 0xc] // 64890d00000000 | mov dword ptr fs:[0], ecx // 59 | pop ecx // 8b4df0 | mov ecx, dword ptr [ebp - 0x10] $sequence_4 = { 33c5 50 8d45f4 64a300000000 8bf1 837e5000 757c } // n = 7, score = 300 // 33c5 | xor eax, ebp // 50 | push eax // 8d45f4 | lea eax, dword ptr [ebp - 0xc] // 64a300000000 | mov dword ptr fs:[0], eax // 8bf1 | mov esi, ecx // 837e5000 | cmp dword ptr [esi + 0x50], 0 // 757c | jne 0x7e $sequence_5 = { 85ff 75da 837e1410 897e10 720d 8b06 } // n = 6, score = 300 // 85ff | test edi, edi // 75da | jne 0xffffffdc // 837e1410 | cmp dword ptr [esi + 0x14], 0x10 // 897e10 | mov dword ptr [esi + 0x10], edi // 720d | jb 0xf // 8b06 | mov eax, dword ptr [esi] $sequence_6 = { 8b06 eb02 8bc6 6a08 } // n = 4, score = 300 // 8b06 | mov eax, dword ptr [esi] // eb02 | jmp 4 // 8bc6 | mov eax, esi // 6a08 | push 8 $sequence_7 = { 50 53 e8???????? 8b45cc 83c408 83f810 7242 } // n = 7, score = 300 // 50 | push eax // 53 | push ebx // e8???????? | // 8b45cc | mov eax, dword ptr [ebp - 0x34] // 83c408 | add esp, 8 // 83f810 | cmp eax, 0x10 // 7242 | jb 0x44 $sequence_8 = { e8???????? 8d4dbc e8???????? 8b451c 83f810 0f8289000000 8b4d08 } // n = 7, score = 300 // e8???????? | // 8d4dbc | lea ecx, dword ptr [ebp - 0x44] // e8???????? | // 8b451c | mov eax, dword ptr [ebp + 0x1c] // 83f810 | cmp eax, 0x10 // 0f8289000000 | jb 0x8f // 8b4d08 | mov ecx, dword ptr [ebp + 8] $sequence_9 = { 8bce e8???????? 8b45bc 83f810 7242 8b4da8 } // n = 6, score = 300 // 8bce | mov ecx, esi // e8???????? | // 8b45bc | mov eax, dword ptr [ebp - 0x44] // 83f810 | cmp eax, 0x10 // 7242 | jb 0x44 // 8b4da8 | mov ecx, dword ptr [ebp - 0x58] condition: 7 of them and filesize < 827392 }
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