Actor(s): APT41
There is no description at this point.
rule win_lowkey_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-01-05" version = "1" description = "Detects win.lowkey." 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.lowkey" malpedia_rule_date = "20260105" malpedia_hash = "19b79e7cab4eaf532122e5b45a77dd8f6bb5cc79" malpedia_version = "20251219" 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 = { 4c8bf2 488d8d70010000 33d2 41b800020000 e8???????? } // n = 5, score = 100 // 4c8bf2 | je 0x1713 // 488d8d70010000 | dec eax // 33d2 | test eax, eax // 41b800020000 | dec eax // e8???????? | $sequence_1 = { 83bb7004000002 0f848d010000 83cfff 488d2db7310100 83635000 83632c00 e9???????? } // n = 7, score = 100 // 83bb7004000002 | dec ecx // 0f848d010000 | mov ebx, dword ptr [ebx + 0x28] // 83cfff | dec ecx // 488d2db7310100 | mov esi, dword ptr [ebx + 0x30] // 83635000 | dec ecx // 83632c00 | mov edi, dword ptr [ebx + 0x38] // e9???????? | $sequence_2 = { 498bc2 458bf1 48c1f806 488d0df41e0300 4183e23f 4d03f0 } // n = 6, score = 100 // 498bc2 | mov dword ptr [esp + 0x28], esi // 458bf1 | inc ebp // 48c1f806 | xor eax, eax // 488d0df41e0300 | xor edx, edx // 4183e23f | mov dword ptr [esp + 0x30], esi // 4d03f0 | dec eax $sequence_3 = { 3b15???????? 7350 488bca 4c8d05c9230300 83e13f 488bc2 } // n = 6, score = 100 // 3b15???????? | // 7350 | mov eax, 0x68 // 488bca | or eax, 0xffffffff // 4c8d05c9230300 | dec eax // 83e13f | mov ecx, dword ptr [esp + 0x38] // 488bc2 | dec eax $sequence_4 = { 48898424d0000000 4533c0 488b4708 488bd5 48898424e0000000 } // n = 5, score = 100 // 48898424d0000000 | dec eax // 4533c0 | lea ebp, [esp - 0x2090] // 488b4708 | mov eax, 0x2190 // 488bd5 | inc ecx // 48898424e0000000 | push ebp $sequence_5 = { 488b0d???????? 488b5210 488b8900040000 ff15???????? 488b15???????? 4533c0 } // n = 6, score = 100 // 488b0d???????? | // 488b5210 | mov word ptr [ebp - 0x40], dx // 488b8900040000 | dec ebx // ff15???????? | // 488b15???????? | // 4533c0 | mov edx, dword ptr [esi + edi*8] $sequence_6 = { 85c0 0f94c3 8bc3 488b4c2478 } // n = 4, score = 100 // 85c0 | dec eax // 0f94c3 | mov ebx, eax // 8bc3 | dec eax // 488b4c2478 | lea edx, [0x2f7d0] $sequence_7 = { 33d2 488bc8 ff15???????? 488d1556260200 } // n = 4, score = 100 // 33d2 | je 0x310 // 488bc8 | dec ecx // ff15???????? | // 488d1556260200 | dec eax $sequence_8 = { 488bcf e8???????? 488d4df7 e8???????? 488d155cfd0100 488d4df7 e8???????? } // n = 7, score = 100 // 488bcf | mov ecx, 0x1388 // e8???????? | // 488d4df7 | dec eax // e8???????? | // 488d155cfd0100 | lea edx, [0x224b0] // 488d4df7 | dec eax // e8???????? | $sequence_9 = { 488d15c10d0200 4533c0 48895c2420 488b01 ff5020 488b4c2450 4c8d4de8 } // n = 7, score = 100 // 488d15c10d0200 | je 0x61e // 4533c0 | movzx eax, word ptr [esp + 0x65] // 48895c2420 | cmp ax, si // 488b01 | jne 0x4c7 // ff5020 | dec eax // 488b4c2450 | lea edx, [esp + 0x170] // 4c8d4de8 | test eax, eax condition: 7 of them and filesize < 643072 }
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