rule win_friedex_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.friedex." 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.friedex" malpedia_rule_date = "20260916" malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6" malpedia_version = "20260917" 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 = { 57 6a2a 5f 6a3f 5b 6a02 } // n = 6, score = 800 // 57 | push edi // 6a2a | push 0x2a // 5f | pop edi // 6a3f | push 0x3f // 5b | pop ebx // 6a02 | push 2 $sequence_1 = { 8bd8 8d7102 eb1d 32c0 eb39 663bfa 7410 } // n = 7, score = 800 // 8bd8 | mov ebx, eax // 8d7102 | lea esi, [ecx + 2] // eb1d | jmp 0x1f // 32c0 | xor al, al // eb39 | jmp 0x3b // 663bfa | cmp di, dx // 7410 | je 0x12 $sequence_2 = { 8bc8 e8???????? 57 8bc8 e8???????? 6a26 } // n = 6, score = 800 // 8bc8 | mov ecx, eax // e8???????? | // 57 | push edi // 8bc8 | mov ecx, eax // e8???????? | // 6a26 | push 0x26 $sequence_3 = { 663bf7 7416 663bf2 7405 663bf3 } // n = 5, score = 800 // 663bf7 | cmp si, di // 7416 | je 0x18 // 663bf2 | cmp si, dx // 7405 | je 7 // 663bf3 | cmp si, bx $sequence_4 = { 663938 74f9 33c9 663908 0f94c0 } // n = 5, score = 800 // 663938 | cmp word ptr [eax], di // 74f9 | je 0xfffffffb // 33c9 | xor ecx, ecx // 663908 | cmp word ptr [eax], cx // 0f94c0 | sete al $sequence_5 = { 8bda 0fb711 6685d2 744a 0fb738 663b7c2410 7514 } // n = 7, score = 800 // 8bda | mov ebx, edx // 0fb711 | movzx edx, word ptr [ecx] // 6685d2 | test dx, dx // 744a | je 0x4c // 0fb738 | movzx edi, word ptr [eax] // 663b7c2410 | cmp di, word ptr [esp + 0x10] // 7514 | jne 0x16 $sequence_6 = { 5b 6a02 897c2414 5d eb16 } // n = 5, score = 800 // 5b | pop ebx // 6a02 | push 2 // 897c2414 | mov dword ptr [esp + 0x14], edi // 5d | pop ebp // eb16 | jmp 0x18 $sequence_7 = { c20400 8b4c2404 8d44240c 50 ff74240c e8???????? 8b442404 } // n = 7, score = 800 // c20400 | ret 4 // 8b4c2404 | mov ecx, dword ptr [esp + 4] // 8d44240c | lea eax, [esp + 0xc] // 50 | push eax // ff74240c | push dword ptr [esp + 0xc] // e8???????? | // 8b442404 | mov eax, dword ptr [esp + 4] $sequence_8 = { e8???????? 8d0d4430a500 31d2 8b75f8 89461c } // n = 5, score = 100 // e8???????? | // 8d0d4430a500 | lea ecx, [0xa53044] // 31d2 | xor edx, edx // 8b75f8 | mov esi, dword ptr [ebp - 8] // 89461c | mov dword ptr [esi + 0x1c], eax $sequence_9 = { 83c414 5b 5d c3 8b45f0 8b0c850440a500 } // n = 6, score = 100 // 83c414 | add esp, 0x14 // 5b | pop ebx // 5d | pop ebp // c3 | ret // 8b45f0 | mov eax, dword ptr [ebp - 0x10] // 8b0c850440a500 | mov ecx, dword ptr [eax*4 + 0xa54004] $sequence_10 = { 53 83ec54 8d055a23a500 31c9 8d55d8 803d????????e9 8955d4 } // n = 7, score = 100 // 53 | push ebx // 83ec54 | sub esp, 0x54 // 8d055a23a500 | lea eax, [0xa5235a] // 31c9 | xor ecx, ecx // 8d55d8 | lea edx, [ebp - 0x28] // 803d????????e9 | // 8955d4 | mov dword ptr [ebp - 0x2c], edx $sequence_11 = { 8d055a23a500 5d c3 55 89e5 56 57 } // n = 7, score = 100 // 8d055a23a500 | lea eax, [0xa5235a] // 5d | pop ebp // c3 | ret // 55 | push ebp // 89e5 | mov ebp, esp // 56 | push esi // 57 | push edi $sequence_12 = { e8???????? 8d0da030a500 890424 894c2404 e8???????? 8d0d4430a500 } // n = 6, score = 100 // e8???????? | // 8d0da030a500 | lea ecx, [0xa530a0] // 890424 | mov dword ptr [esp], eax // 894c2404 | mov dword ptr [esp + 4], ecx // e8???????? | // 8d0d4430a500 | lea ecx, [0xa53044] $sequence_13 = { c744240400000000 8945f4 8955f0 e8???????? 8d0da030a500 890424 } // n = 6, score = 100 // c744240400000000 | mov dword ptr [esp + 4], 0 // 8945f4 | mov dword ptr [ebp - 0xc], eax // 8955f0 | mov dword ptr [ebp - 0x10], edx // e8???????? | // 8d0da030a500 | lea ecx, [0xa530a0] // 890424 | mov dword ptr [esp], eax $sequence_14 = { 31d2 8a2c057530a500 83c001 38e9 } // n = 4, score = 100 // 31d2 | xor edx, edx // 8a2c057530a500 | mov ch, byte ptr [eax + 0xa53075] // 83c001 | add eax, 1 // 38e9 | cmp cl, ch $sequence_15 = { 894628 890c24 c744240400000000 8955dc e8???????? 8d0de830a500 890424 } // n = 7, score = 100 // 894628 | mov dword ptr [esi + 0x28], eax // 890c24 | mov dword ptr [esp], ecx // c744240400000000 | mov dword ptr [esp + 4], 0 // 8955dc | mov dword ptr [ebp - 0x24], edx // e8???????? | // 8d0de830a500 | lea ecx, [0xa530e8] // 890424 | mov dword ptr [esp], eax condition: 7 of them and filesize < 204800 }