A ransomware first observed in July 2021.
rule win_lockfile_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-12-06" 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 = "20231130" malpedia_hash = "fc8a0e9f343f6d6ded9e7df1a64dac0cc68d7351" malpedia_version = "20230808" 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 = { 418bdc 33d9 8bcb 4123cf 4133cc 03d1 8955bb } // n = 7, score = 200 // 418bdc | sub ebx, eax // 33d9 | nop word ptr [eax + eax] // 8bcb | movdqu xmm0, xmmword ptr [eax - 0x10] // 4123cf | dec eax // 4133cc | add esi, 0x10 // 03d1 | movdqu xmm1, xmmword ptr [eax + edx - 0x10] // 8955bb | movdqu xmm2, xmmword ptr [edx + eax] $sequence_1 = { 488b4b58 49894a48 488b5360 49895250 48837b6010 7731 41c6424101 } // n = 7, score = 200 // 488b4b58 | movups xmmword ptr [eax + 0x20], xmm0 // 49894a48 | dec ecx // 488b5360 | mov ebx, dword ptr [ebp] // 49895250 | dec ecx // 48837b6010 | sub ebx, esp // 7731 | xor edx, edx // 41c6424101 | dec eax $sequence_2 = { 488bf1 33d2 e8???????? 33d2 48895618 48895620 } // n = 6, score = 200 // 488bf1 | dec eax // 33d2 | mov dword ptr [ebp + 0x58], edx // e8???????? | // 33d2 | dec ecx // 48895618 | cmp ecx, edx // 48895620 | inc ecx $sequence_3 = { e9???????? 4c8d4c245c 4c8d4570 488d15b31e0600 488d8d70020000 e8???????? 488d8d70020000 } // n = 7, score = 200 // e9???????? | // 4c8d4c245c | dec ecx // 4c8d4570 | mov eax, dword ptr [esp + 0x60] // 488d15b31e0600 | dec esp // 488d8d70020000 | cmp eax, ecx // e8???????? | // 488d8d70020000 | dec eax $sequence_4 = { 85c0 7411 836530fe 488b4d38 4883c178 e8???????? } // n = 6, score = 200 // 85c0 | cmp eax, ebx // 7411 | jae 0xa06 // 836530fe | dec ecx // 488b4d38 | cmp ebx, eax // 4883c178 | jae 0xa11 // e8???????? | $sequence_5 = { 57 4883ec20 8bfa 488bd9 488b4908 4885c9 740b } // n = 7, score = 200 // 57 | cmp ecx, ebx // 4883ec20 | dec eax // 8bfa | mov ebx, dword ptr [ebp + 0x50] // 488bd9 | dec eax // 488b4908 | adc edx, 0 // 4885c9 | dec eax // 740b | mov dword ptr [ebp - 0x10], edx $sequence_6 = { 0f845c010000 83792801 0f8552010000 e8???????? 8bd8 483bde 480f42de } // n = 7, score = 200 // 0f845c010000 | cmp ebx, edx // 83792801 | dec esp // 0f8552010000 | cmp ebx, edx // e8???????? | // 8bd8 | dec ecx // 483bde | adc eax, 0 // 480f42de | dec ecx $sequence_7 = { 0f84a5000000 488b0d???????? 488b15???????? 4c3bc1 750d 488bc1 48d1e8 } // n = 7, score = 200 // 0f84a5000000 | mov ebx, dword ptr [ebp - 0x61] // 488b0d???????? | // 488b15???????? | // 4c3bc1 | dec eax // 750d | adc edi, 0 // 488bc1 | dec ecx // 48d1e8 | cmp esi, esi $sequence_8 = { 41c1c802 4123cb 418bd1 0bc8 c1c205 03cd 418bc0 } // n = 7, score = 200 // 41c1c802 | dec ecx // 4123cb | lea ecx, [eax - 1] // 418bd1 | dec eax // 0bc8 | lea ecx, [eax + ecx*8] // c1c205 | dec eax // 03cd | cmp dword ptr [ecx], 0 // 418bc0 | dec ebp $sequence_9 = { 88458c 8b4580 0409 3465 88458d 8b4580 040a } // n = 7, score = 200 // 88458c | dec esp // 8b4580 | lea eax, [ecx + eax] // 0409 | dec eax // 3465 | mul dword ptr [ebx + 0x68] // 88458d | dec edi // 8b4580 | lea esi, [esp + edi] // 040a | dec eax condition: 7 of them and filesize < 1163264 }
If your designated proposal does not fit in any other category, feel free to write a free-text in the comment field below. Changes regarding references should be proposed on the Malpedia library page.
Your suggestion will be reviewed before being published. Thank you for contributing!
YYYY-MM-DD
YYYY-MM
YYYY