Actor(s): Sowbug
There is no description at this point.
rule win_felismus_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-12-06" version = "1" description = "Detects win.felismus." 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.felismus" 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 = { ff15???????? 8b35???????? 83c404 53 ffd6 8b442410 } // n = 6, score = 100 // ff15???????? | // 8b35???????? | // 83c404 | add esp, 4 // 53 | push ebx // ffd6 | call esi // 8b442410 | mov eax, dword ptr [esp + 0x10] $sequence_1 = { 8b4e08 8b560c 89442418 8b4610 894c241c 89442424 } // n = 6, score = 100 // 8b4e08 | mov ecx, dword ptr [esi + 8] // 8b560c | mov edx, dword ptr [esi + 0xc] // 89442418 | mov dword ptr [esp + 0x18], eax // 8b4610 | mov eax, dword ptr [esi + 0x10] // 894c241c | mov dword ptr [esp + 0x1c], ecx // 89442424 | mov dword ptr [esp + 0x24], eax $sequence_2 = { 89542410 8b5110 56 2be8 57 89542420 bb01000000 } // n = 7, score = 100 // 89542410 | mov dword ptr [esp + 0x10], edx // 8b5110 | mov edx, dword ptr [ecx + 0x10] // 56 | push esi // 2be8 | sub ebp, eax // 57 | push edi // 89542420 | mov dword ptr [esp + 0x20], edx // bb01000000 | mov ebx, 1 $sequence_3 = { 8d5640 8bfa f3ab 8b4618 33c9 85c0 7e24 } // n = 7, score = 100 // 8d5640 | lea edx, [esi + 0x40] // 8bfa | mov edi, edx // f3ab | rep stosd dword ptr es:[edi], eax // 8b4618 | mov eax, dword ptr [esi + 0x18] // 33c9 | xor ecx, ecx // 85c0 | test eax, eax // 7e24 | jle 0x26 $sequence_4 = { 66ab aa b940000000 33c0 8dbc24b1050000 } // n = 5, score = 100 // 66ab | stosw word ptr es:[edi], ax // aa | stosb byte ptr es:[edi], al // b940000000 | mov ecx, 0x40 // 33c0 | xor eax, eax // 8dbc24b1050000 | lea edi, [esp + 0x5b1] $sequence_5 = { 85c0 740f 8d8c2414010000 68???????? 51 eb0d 8d942414010000 } // n = 7, score = 100 // 85c0 | test eax, eax // 740f | je 0x11 // 8d8c2414010000 | lea ecx, [esp + 0x114] // 68???????? | // 51 | push ecx // eb0d | jmp 0xf // 8d942414010000 | lea edx, [esp + 0x114] $sequence_6 = { 8b442424 50 56 ff15???????? 56 ff15???????? 83f8ff } // n = 7, score = 100 // 8b442424 | mov eax, dword ptr [esp + 0x24] // 50 | push eax // 56 | push esi // ff15???????? | // 56 | push esi // ff15???????? | // 83f8ff | cmp eax, -1 $sequence_7 = { 7cd0 8b461c 8bce 50 e8???????? 8b7e1c } // n = 6, score = 100 // 7cd0 | jl 0xffffffd2 // 8b461c | mov eax, dword ptr [esi + 0x1c] // 8bce | mov ecx, esi // 50 | push eax // e8???????? | // 8b7e1c | mov edi, dword ptr [esi + 0x1c] $sequence_8 = { 51 8bfb 83c9ff 33c0 895514 f2ae f7d1 } // n = 7, score = 100 // 51 | push ecx // 8bfb | mov edi, ebx // 83c9ff | or ecx, 0xffffffff // 33c0 | xor eax, eax // 895514 | mov dword ptr [ebp + 0x14], edx // f2ae | repne scasb al, byte ptr es:[edi] // f7d1 | not ecx $sequence_9 = { 83c408 85ff 742b 57 ff15???????? 83f816 7e1f } // n = 7, score = 100 // 83c408 | add esp, 8 // 85ff | test edi, edi // 742b | je 0x2d // 57 | push edi // ff15???????? | // 83f816 | cmp eax, 0x16 // 7e1f | jle 0x21 condition: 7 of them and filesize < 204800 }
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