rule win_plugx_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.plugx." 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.plugx" 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 = { 56 8b750c 8b4604 050070ffff } // n = 4, score = 1400 // 56 | push esi // 8b750c | mov esi, dword ptr [ebp + 0xc] // 8b4604 | mov eax, dword ptr [esi + 4] // 050070ffff | add eax, 0xffff7000 $sequence_1 = { 0145f4 8b45fc 0fafc3 33d2 } // n = 4, score = 1400 // 0145f4 | add dword ptr [ebp - 0xc], eax // 8b45fc | mov eax, dword ptr [ebp - 4] // 0fafc3 | imul eax, ebx // 33d2 | xor edx, edx $sequence_2 = { 51 56 57 6a1c 8bf8 e8???????? 8bf0 } // n = 7, score = 1400 // 51 | push ecx // 56 | push esi // 57 | push edi // 6a1c | push 0x1c // 8bf8 | mov edi, eax // e8???????? | // 8bf0 | mov esi, eax $sequence_3 = { 51 53 6a00 6a00 6a02 ffd0 } // n = 6, score = 1400 // 51 | push ecx // 53 | push ebx // 6a00 | push 0 // 6a00 | push 0 // 6a02 | push 2 // ffd0 | call eax $sequence_4 = { 55 8bec 8b450c 81780402700000 } // n = 4, score = 1400 // 55 | push ebp // 8bec | mov ebp, esp // 8b450c | mov eax, dword ptr [ebp + 0xc] // 81780402700000 | cmp dword ptr [eax + 4], 0x7002 $sequence_5 = { 55 8bec a1???????? 83ec5c 53 } // n = 5, score = 1400 // 55 | push ebp // 8bec | mov ebp, esp // a1???????? | // 83ec5c | sub esp, 0x5c // 53 | push ebx $sequence_6 = { 33d2 f7f3 33d2 8945fc } // n = 4, score = 1400 // 33d2 | xor edx, edx // f7f3 | div ebx // 33d2 | xor edx, edx // 8945fc | mov dword ptr [ebp - 4], eax $sequence_7 = { e8???????? 85c0 7508 e8???????? 8945fc } // n = 5, score = 1000 // e8???????? | // 85c0 | test eax, eax // 7508 | jne 0xa // e8???????? | // 8945fc | mov dword ptr [ebp - 4], eax $sequence_8 = { e8???????? 3de5030000 7407 e8???????? } // n = 4, score = 1000 // e8???????? | // 3de5030000 | cmp eax, 0x3e5 // 7407 | je 9 // e8???????? | $sequence_9 = { 85c0 7413 e8???????? 3de5030000 } // n = 4, score = 1000 // 85c0 | test eax, eax // 7413 | je 0x15 // e8???????? | // 3de5030000 | cmp eax, 0x3e5 $sequence_10 = { e8???????? 85c0 7407 b84f050000 } // n = 4, score = 900 // e8???????? | // 85c0 | test eax, eax // 7407 | je 9 // b84f050000 | mov eax, 0x54f $sequence_11 = { 50 ff15???????? a3???????? 8b4d18 } // n = 4, score = 900 // 50 | push eax // ff15???????? | // a3???????? | // 8b4d18 | mov ecx, dword ptr [ebp + 0x18] $sequence_12 = { e8???????? 85c0 750a e8???????? 8945fc } // n = 5, score = 800 // e8???????? | // 85c0 | test eax, eax // 750a | jne 0xc // e8???????? | // 8945fc | mov dword ptr [ebp - 4], eax $sequence_13 = { 85c0 750d e8???????? 8945f4 } // n = 4, score = 700 // 85c0 | test eax, eax // 750d | jne 0xf // e8???????? | // 8945f4 | mov dword ptr [ebp - 0xc], eax $sequence_14 = { 51 6a00 6800100000 6800100000 68ff000000 6a00 6803000040 } // n = 7, score = 600 // 51 | push ecx // 6a00 | push 0 // 6800100000 | push 0x1000 // 6800100000 | push 0x1000 // 68ff000000 | push 0xff // 6a00 | push 0 // 6803000040 | push 0x40000003 $sequence_15 = { 50 ff75e8 6802000080 e8???????? } // n = 4, score = 500 // 50 | push eax // ff75e8 | push dword ptr [ebp - 0x18] // 6802000080 | push 0x80000002 // e8???????? | $sequence_16 = { 55 53 57 56 ffd0 } // n = 5, score = 400 // 55 | push ebp // 53 | push ebx // 57 | push edi // 56 | push esi // ffd0 | call eax $sequence_17 = { 89742434 89f1 8b442434 e8???????? } // n = 4, score = 400 // 89742434 | mov dword ptr [esp + 0x34], esi // 89f1 | mov ecx, esi // 8b442434 | mov eax, dword ptr [esp + 0x34] // e8???????? | $sequence_18 = { 6808020000 6a00 ff74242c e8???????? } // n = 4, score = 400 // 6808020000 | push 0x208 // 6a00 | push 0 // ff74242c | push dword ptr [esp + 0x2c] // e8???????? | $sequence_19 = { 89442424 8b442424 6808020000 6a00 } // n = 4, score = 400 // 89442424 | mov dword ptr [esp + 0x24], eax // 8b442424 | mov eax, dword ptr [esp + 0x24] // 6808020000 | push 0x208 // 6a00 | push 0 $sequence_20 = { 50 56 ffb42480000000 ff15???????? } // n = 4, score = 400 // 50 | push eax // 56 | push esi // ffb42480000000 | push dword ptr [esp + 0x80] // ff15???????? | $sequence_21 = { 6808020000 6a00 ff74245c e8???????? } // n = 4, score = 300 // 6808020000 | push 0x208 // 6a00 | push 0 // ff74245c | push dword ptr [esp + 0x5c] // e8???????? | $sequence_22 = { bbe6000000 89d7 83e219 f7d7 } // n = 4, score = 300 // bbe6000000 | mov ebx, 0xe6 // 89d7 | mov edi, edx // 83e219 | and edx, 0x19 // f7d7 | not edi $sequence_23 = { c6410c00 e8???????? 31db 57 53 } // n = 5, score = 300 // c6410c00 | mov byte ptr [ecx + 0xc], 0 // e8???????? | // 31db | xor ebx, ebx // 57 | push edi // 53 | push ebx $sequence_24 = { c3 b8???????? c3 50 64a118000000 } // n = 5, score = 300 // c3 | ret // b8???????? | // c3 | ret // 50 | push eax // 64a118000000 | mov eax, dword ptr fs:[0x18] $sequence_25 = { 6a5c ff74241c e8???????? 83c408 } // n = 4, score = 300 // 6a5c | push 0x5c // ff74241c | push dword ptr [esp + 0x1c] // e8???????? | // 83c408 | add esp, 8 condition: 7 of them and filesize < 1284096 }