A ransomware first observed in July 2021.
rule win_lockfile_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.lockfile." 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.lockfile" 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 = { 488d0d293d0700 8b440104 8b4c243c 33c8 8bc1 8944243c 8b442440 } // n = 7, score = 200 // 488d0d293d0700 | adc edi, 0 // 8b440104 | dec eax // 8b4c243c | adc edi, 0 // 33c8 | dec ecx // 8bc1 | mul dword ptr [ecx + 0x38] // 8944243c | dec esp // 8b442440 | lea edx, [edi + ebx] $sequence_1 = { 410fb6d2 ff5060 488b8c2480000000 4833cc e8???????? 4881c498000000 c3 } // n = 7, score = 200 // 410fb6d2 | add al, 6 // ff5060 | xor al, 0x72 // 488b8c2480000000 | mov byte ptr [ebp - 0x76], al // 4833cc | mov eax, dword ptr [ebp - 0x80] // e8???????? | // 4881c498000000 | add al, 7 // c3 | mov eax, dword ptr [ebp - 0x80] $sequence_2 = { 4133c5 03d0 488d05d7270300 031488 4103d0 03d6 8b75bb } // n = 7, score = 200 // 4133c5 | add al, 0x1b // 03d0 | mov eax, dword ptr [ebp - 0x30] // 488d05d7270300 | add al, 0x1b // 031488 | xor al, 0x69 // 4103d0 | mov byte ptr [ebp - 0x11], al // 03d6 | mov eax, dword ptr [ebp - 0x30] // 8b75bb | add al, 0x1c $sequence_3 = { 4889842480000000 488d1510da0400 488d4c2420 e8???????? 90 488d542420 488d4c2440 } // n = 7, score = 200 // 4889842480000000 | xor ecx, edx // 488d1510da0400 | inc ecx // 488d4c2420 | ror ecx, 2 // e8???????? | // 90 | inc ecx // 488d542420 | mov ecx, eax // 488d4c2440 | or ecx, ebx $sequence_4 = { 041c 346b 88442460 8b442440 041d 3465 88442461 } // n = 7, score = 200 // 041c | lea eax, [ecx - 1] // 346b | dec eax // 88442460 | lea eax, [edx + eax*8] // 8b442440 | dec eax // 041d | cmp dword ptr [eax], esi // 3465 | jne 0x212 // 88442461 | dec eax $sequence_5 = { 4d2bc1 7415 0f1f4000 48836b2001 7504 4c897b18 4983e801 } // n = 7, score = 200 // 4d2bc1 | dec ecx // 7415 | adc ebp, 0 // 0f1f4000 | dec ecx // 48836b2001 | cmp edi, esi // 7504 | dec esp // 4c897b18 | mov esi, dword ptr [ebp + 0x50] // 4983e801 | dec ecx $sequence_6 = { 4c2bc3 420fb60411 3201 488d4901 440ac8 4983e801 75ec } // n = 7, score = 200 // 4c2bc3 | dec ecx // 420fb60411 | add eax, eax // 3201 | dec ecx // 488d4901 | cmp eax, eax // 440ac8 | dec eax // 4983e801 | adc edx, 0 // 75ec | dec esp $sequence_7 = { 3468 8845e2 8b45d0 040f 3465 8845e3 8b45d0 } // n = 7, score = 200 // 3468 | mov dword ptr [ebp - 0x24], edx // 8845e2 | movups xmmword ptr [ebp - 0x20], xmm1 // 8b45d0 | inc esp // 040f | mov esi, edx // 3465 | inc esp // 8845e3 | mov esp, ebx // 8b45d0 | cpuid $sequence_8 = { 488d0d03350700 8b440101 8b4c243c 33c8 8bc1 8944243c 8b44244c } // n = 7, score = 200 // 488d0d03350700 | mov dword ptr [ecx + 0x20], eax // 8b440101 | dec eax // 8b4c243c | mov eax, dword ptr [ebp + 0x77] // 33c8 | dec ebp // 8bc1 | lea ebx, [eax + edi] // 8944243c | dec eax // 8b44244c | mov eax, dword ptr [eax + 0x78] $sequence_9 = { 4833c4 48898590010000 4c8bad08020000 0f57c0 0f1185b0000000 0f1185c0000000 0f1185d0000000 } // n = 7, score = 200 // 4833c4 | mov dword ptr [ebp - 0x20], ecx // 48898590010000 | dec eax // 4c8bad08020000 | mov dword ptr [ebp - 0x18], edi // 0f57c0 | dec eax // 0f1185b0000000 | mov edx, dword ptr [ebp + 0x20] // 0f1185c0000000 | dec ebp // 0f1185d0000000 | mov eax, edx condition: 7 of them and filesize < 1163264 }
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