rule win_phorpiex_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.phorpiex." 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.phorpiex" 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 = { 6a00 ff15???????? ff15???????? 50 e8???????? } // n = 5, score = 1100 // 6a00 | push 0 // ff15???????? | // ff15???????? | // 50 | push eax // e8???????? | $sequence_1 = { ff15???????? 85c0 740f 6a07 } // n = 4, score = 1100 // ff15???????? | // 85c0 | test eax, eax // 740f | je 0x11 // 6a07 | push 7 $sequence_2 = { ff15???????? 85c0 741f 6880000000 } // n = 4, score = 1000 // ff15???????? | // 85c0 | test eax, eax // 741f | je 0x21 // 6880000000 | push 0x80 $sequence_3 = { 6a00 6a20 6a00 6a00 6a00 8b5508 } // n = 6, score = 900 // 6a00 | push 0 // 6a20 | push 0x20 // 6a00 | push 0 // 6a00 | push 0 // 6a00 | push 0 // 8b5508 | mov edx, dword ptr [ebp + 8] $sequence_4 = { 83c410 6a00 6a02 6a02 6a00 6a00 6800000040 } // n = 7, score = 900 // 83c410 | add esp, 0x10 // 6a00 | push 0 // 6a02 | push 2 // 6a02 | push 2 // 6a00 | push 0 // 6a00 | push 0 // 6800000040 | push 0x40000000 $sequence_5 = { 50 e8???????? 83c404 e8???????? e8???????? ff15???????? 6a00 } // n = 7, score = 800 // 50 | push eax // e8???????? | // 83c404 | add esp, 4 // e8???????? | // e8???????? | // ff15???????? | // 6a00 | push 0 $sequence_6 = { 6a01 6a00 68???????? e8???????? 83c40c 33c0 } // n = 6, score = 800 // 6a01 | push 1 // 6a00 | push 0 // 68???????? | // e8???????? | // 83c40c | add esp, 0xc // 33c0 | xor eax, eax $sequence_7 = { 52 683f000f00 6a00 68???????? 6802000080 ff15???????? 85c0 } // n = 7, score = 700 // 52 | push edx // 683f000f00 | push 0xf003f // 6a00 | push 0 // 68???????? | // 6802000080 | push 0x80000002 // ff15???????? | // 85c0 | test eax, eax $sequence_8 = { 6a00 682a800000 6a00 ff15???????? } // n = 4, score = 700 // 6a00 | push 0 // 682a800000 | push 0x802a // 6a00 | push 0 // ff15???????? | $sequence_9 = { 68???????? ff15???????? 8d85f8fdffff 50 68???????? } // n = 5, score = 700 // 68???????? | // ff15???????? | // 8d85f8fdffff | lea eax, [ebp - 0x208] // 50 | push eax // 68???????? | $sequence_10 = { ff15???????? 6a00 ff15???????? 85c0 7418 } // n = 5, score = 700 // ff15???????? | // 6a00 | push 0 // ff15???????? | // 85c0 | test eax, eax // 7418 | je 0x1a $sequence_11 = { 6a01 ff15???????? ff15???????? b001 } // n = 4, score = 700 // 6a01 | push 1 // ff15???????? | // ff15???????? | // b001 | mov al, 1 $sequence_12 = { 68???????? ff15???????? e9???????? 8d45fc 50 } // n = 5, score = 600 // 68???????? | // ff15???????? | // e9???????? | // 8d45fc | lea eax, [ebp - 4] // 50 | push eax $sequence_13 = { f7f9 81c210270000 52 e8???????? 99 } // n = 5, score = 600 // f7f9 | idiv ecx // 81c210270000 | add edx, 0x2710 // 52 | push edx // e8???????? | // 99 | cdq $sequence_14 = { 83c201 8955f0 8b45f8 89856cffffff 8b4df0 8b550c 833c8a00 } // n = 7, score = 600 // 83c201 | add edx, 1 // 8955f0 | mov dword ptr [ebp - 0x10], edx // 8b45f8 | mov eax, dword ptr [ebp - 8] // 89856cffffff | mov dword ptr [ebp - 0x94], eax // 8b4df0 | mov ecx, dword ptr [ebp - 0x10] // 8b550c | mov edx, dword ptr [ebp + 0xc] // 833c8a00 | cmp dword ptr [edx + ecx*4], 0 $sequence_15 = { 7429 8b45f8 50 ff15???????? 8945fc 837dfc00 7416 } // n = 7, score = 600 // 7429 | je 0x2b // 8b45f8 | mov eax, dword ptr [ebp - 8] // 50 | push eax // ff15???????? | // 8945fc | mov dword ptr [ebp - 4], eax // 837dfc00 | cmp dword ptr [ebp - 4], 0 // 7416 | je 0x18 $sequence_16 = { 7440 6a01 ff15???????? 8945f8 837df800 } // n = 5, score = 600 // 7440 | je 0x42 // 6a01 | push 1 // ff15???????? | // 8945f8 | mov dword ptr [ebp - 8], eax // 837df800 | cmp dword ptr [ebp - 8], 0 $sequence_17 = { 8b450c 8b4c9008 51 e8???????? 83c404 85c0 } // n = 6, score = 600 // 8b450c | mov eax, dword ptr [ebp + 0xc] // 8b4c9008 | mov ecx, dword ptr [eax + edx*4 + 8] // 51 | push ecx // e8???????? | // 83c404 | add esp, 4 // 85c0 | test eax, eax $sequence_18 = { 6a21 50 e8???????? c60000 } // n = 4, score = 500 // 6a21 | push 0x21 // 50 | push eax // e8???????? | // c60000 | mov byte ptr [eax], 0 $sequence_19 = { 3db7000000 7508 6a00 ff15???????? 6804010000 } // n = 5, score = 500 // 3db7000000 | cmp eax, 0xb7 // 7508 | jne 0xa // 6a00 | push 0 // ff15???????? | // 6804010000 | push 0x104 $sequence_20 = { 3d00010000 7504 83c8ff c3 8b542404 } // n = 5, score = 500 // 3d00010000 | cmp eax, 0x100 // 7504 | jne 6 // 83c8ff | or eax, 0xffffffff // c3 | ret // 8b542404 | mov edx, dword ptr [esp + 4] $sequence_21 = { 50 e8???????? 59 59 85c0 0f85c0000000 } // n = 6, score = 500 // 50 | push eax // e8???????? | // 59 | pop ecx // 59 | pop ecx // 85c0 | test eax, eax // 0f85c0000000 | jne 0xc6 $sequence_22 = { 83c40c e8???????? 99 b960ea0000 } // n = 4, score = 400 // 83c40c | add esp, 0xc // e8???????? | // 99 | cdq // b960ea0000 | mov ecx, 0xea60 $sequence_23 = { 51 8bd0 52 8d84241c020000 68???????? 50 e8???????? } // n = 7, score = 400 // 51 | push ecx // 8bd0 | mov edx, eax // 52 | push edx // 8d84241c020000 | lea eax, [esp + 0x21c] // 68???????? | // 50 | push eax // e8???????? | $sequence_24 = { 1bf6 83deff f7de 1bf6 8b44b30c 83c604 } // n = 6, score = 400 // 1bf6 | sbb esi, esi // 83deff | sbb esi, -1 // f7de | neg esi // 1bf6 | sbb esi, esi // 8b44b30c | mov eax, dword ptr [ebx + esi*4 + 0xc] // 83c604 | add esi, 4 $sequence_25 = { 740e 803e00 7401 46 } // n = 4, score = 400 // 740e | je 0x10 // 803e00 | cmp byte ptr [esi], 0 // 7401 | je 3 // 46 | inc esi $sequence_26 = { 41 663bc2 72f7 53 33c0 56 57 } // n = 7, score = 300 // 41 | inc ecx // 663bc2 | cmp ax, dx // 72f7 | jb 0xfffffff9 // 53 | push ebx // 33c0 | xor eax, eax // 56 | push esi // 57 | push edi $sequence_27 = { 50 8d45ec 50 6805000020 } // n = 4, score = 300 // 50 | push eax // 8d45ec | lea eax, [ebp - 0x14] // 50 | push eax // 6805000020 | push 0x20000005 $sequence_28 = { 57 68e8030000 ff15???????? e8???????? be???????? } // n = 5, score = 300 // 57 | push edi // 68e8030000 | push 0x3e8 // ff15???????? | // e8???????? | // be???????? | $sequence_29 = { 8d45f8 50 8d45e0 50 6805000020 } // n = 5, score = 200 // 8d45f8 | lea eax, [ebp - 8] // 50 | push eax // 8d45e0 | lea eax, [ebp - 0x20] // 50 | push eax // 6805000020 | push 0x20000005 condition: 7 of them and filesize < 2490368 }