Ransomware.
rule win_metadatabin_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2022-04-08" version = "1" description = "Detects win.metadatabin." 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.metadatabin" 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 = { 8b742424 89c3 89d7 89c8 039c24a0000000 83d700 f7e6 } // n = 7, score = 100 // 8b742424 | mov esi, dword ptr [esp + 0x24] // 89c3 | mov ebx, eax // 89d7 | mov edi, edx // 89c8 | mov eax, ecx // 039c24a0000000 | add ebx, dword ptr [esp + 0xa0] // 83d700 | adc edi, 0 // f7e6 | mul esi $sequence_1 = { 8b85b0feffff 19d6 891c24 89ca 89742404 e8???????? 85c0 } // n = 7, score = 100 // 8b85b0feffff | mov eax, dword ptr [ebp - 0x150] // 19d6 | sbb esi, edx // 891c24 | mov dword ptr [esp], ebx // 89ca | mov edx, ecx // 89742404 | mov dword ptr [esp + 4], esi // e8???????? | // 85c0 | test eax, eax $sequence_2 = { f7e6 89c6 89d7 89d8 03b42480000000 83d700 f7a424c0000000 } // n = 7, score = 100 // f7e6 | mul esi // 89c6 | mov esi, eax // 89d7 | mov edi, edx // 89d8 | mov eax, ebx // 03b42480000000 | add esi, dword ptr [esp + 0x80] // 83d700 | adc edi, 0 // f7a424c0000000 | mul dword ptr [esp + 0xc0] $sequence_3 = { 8d55d8 ff37 52 50 ff5108 83c40c 8b45e8 } // n = 7, score = 100 // 8d55d8 | lea edx, dword ptr [ebp - 0x28] // ff37 | push dword ptr [edi] // 52 | push edx // 50 | push eax // ff5108 | call dword ptr [ecx + 8] // 83c40c | add esp, 0xc // 8b45e8 | mov eax, dword ptr [ebp - 0x18] $sequence_4 = { f20f1094248c000000 f20f108c2494000000 899424d8000000 8b94249c000000 894c2424 8b4c2450 f20f11942418010000 } // n = 7, score = 100 // f20f1094248c000000 | movsd xmm2, qword ptr [esp + 0x8c] // f20f108c2494000000 | movsd xmm1, qword ptr [esp + 0x94] // 899424d8000000 | mov dword ptr [esp + 0xd8], edx // 8b94249c000000 | mov edx, dword ptr [esp + 0x9c] // 894c2424 | mov dword ptr [esp + 0x24], ecx // 8b4c2450 | mov ecx, dword ptr [esp + 0x50] // f20f11942418010000 | movsd qword ptr [esp + 0x118], xmm2 $sequence_5 = { 8dbde8feffff 31c0 b90e000000 c785a8feffff00000000 c785acfeffff00000000 f3ab c785b0feffff00000000 } // n = 7, score = 100 // 8dbde8feffff | lea edi, dword ptr [ebp - 0x118] // 31c0 | xor eax, eax // b90e000000 | mov ecx, 0xe // c785a8feffff00000000 | mov dword ptr [ebp - 0x158], 0 // c785acfeffff00000000 | mov dword ptr [ebp - 0x154], 0 // f3ab | rep stosd dword ptr es:[edi], eax // c785b0feffff00000000 | mov dword ptr [ebp - 0x150], 0 $sequence_6 = { b8ffff0700 21c3 b8ffffffff 21c1 8b842430090000 899c24e0020000 894c2468 } // n = 7, score = 100 // b8ffff0700 | mov eax, 0x7ffff // 21c3 | and ebx, eax // b8ffffffff | mov eax, 0xffffffff // 21c1 | and ecx, eax // 8b842430090000 | mov eax, dword ptr [esp + 0x930] // 899c24e0020000 | mov dword ptr [esp + 0x2e0], ebx // 894c2468 | mov dword ptr [esp + 0x68], ecx $sequence_7 = { f7e3 01c8 8b4c2424 89842414020000 0fb68424b0010000 11c2 89f0 } // n = 7, score = 100 // f7e3 | mul ebx // 01c8 | add eax, ecx // 8b4c2424 | mov ecx, dword ptr [esp + 0x24] // 89842414020000 | mov dword ptr [esp + 0x214], eax // 0fb68424b0010000 | movzx eax, byte ptr [esp + 0x1b0] // 11c2 | adc edx, eax // 89f0 | mov eax, esi $sequence_8 = { 57 56 83ec48 8d0449 89d7 be01000000 83f802 } // n = 7, score = 100 // 57 | push edi // 56 | push esi // 83ec48 | sub esp, 0x48 // 8d0449 | lea eax, dword ptr [ecx + ecx*2] // 89d7 | mov edi, edx // be01000000 | mov esi, 1 // 83f802 | cmp eax, 2 $sequence_9 = { 89f9 8b542450 68???????? e8???????? 83c404 0f0b 8b54243c } // n = 7, score = 100 // 89f9 | mov ecx, edi // 8b542450 | mov edx, dword ptr [esp + 0x50] // 68???????? | // e8???????? | // 83c404 | add esp, 4 // 0f0b | ud2 // 8b54243c | mov edx, dword ptr [esp + 0x3c] condition: 7 of them and filesize < 1263616 }
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