Actor(s): Lazarus Group
There is no description at this point.
rule win_lazarloader_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2023-12-06" version = "1" description = "Detects win.lazarloader." 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.lazarloader" 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 = { 483b0d???????? 7417 488d059c4f0100 483bc8 } // n = 4, score = 100 // 483b0d???????? | // 7417 | dec eax // 488d059c4f0100 | sar eax, 6 // 483bc8 | dec eax $sequence_1 = { 7528 48833d????????00 741e 488d0d30a80100 e8???????? 85c0 740e } // n = 7, score = 100 // 7528 | dec eax // 48833d????????00 | // 741e | mov esi, dword ptr [esp + 0x60] // 488d0d30a80100 | dec ecx // e8???????? | // 85c0 | xor edx, eax // 740e | dec edx $sequence_2 = { 8bc2 488d154241ffff c1e803 89442438 448be0 89442440 85c0 } // n = 7, score = 100 // 8bc2 | movzx ecx, word ptr [esp + 0x30] // 488d154241ffff | mov word ptr [eax], cx // c1e803 | dec eax // 89442438 | mov eax, dword ptr [esp + 0x68] // 448be0 | dec eax // 89442440 | add eax, 2 // 85c0 | dec eax $sequence_3 = { 488d0563810000 488bd9 483bc8 7417 8b815c010000 } // n = 5, score = 100 // 488d0563810000 | dec eax // 488bd9 | and dword ptr [esp + 0x38], 0 // 483bc8 | dec esp // 7417 | lea eax, [esp + 0x38] // 8b815c010000 | mov edi, ecx $sequence_4 = { 4889542410 48894c2408 57 4881ece0080000 33c0 66898424a0000000 488d8424a2000000 } // n = 7, score = 100 // 4889542410 | mov esi, eax // 48894c2408 | mov ebp, edx // 57 | dec esp // 4881ece0080000 | lea ecx, [0xac74] // 33c0 | dec esp // 66898424a0000000 | mov esi, ecx // 488d8424a2000000 | dec esp $sequence_5 = { 4c8bea 4b8b8cf770c10100 4c8b15???????? 4883cfff 418bc2 498bd2 4833d1 } // n = 7, score = 100 // 4c8bea | mov eax, dword ptr [esp + 0x40] // 4b8b8cf770c10100 | mov ecx, eax // 4c8b15???????? | // 4883cfff | dec eax // 418bc2 | mov dword ptr [esp + 0x58], eax // 498bd2 | dec eax // 4833d1 | mov ecx, dword ptr [esp + 0x60] $sequence_6 = { 8bcf e8???????? 488bd7 4c8d05fecd0000 83e23f 488bcf 48c1f906 } // n = 7, score = 100 // 8bcf | mov word ptr [esp + 0x40], ax // e8???????? | // 488bd7 | mov eax, 0x62 // 4c8d05fecd0000 | mov word ptr [esp + 0x42], ax // 83e23f | mov eax, 0x69 // 488bcf | mov word ptr [esp + 0x44], ax // 48c1f906 | mov word ptr [esp + 0x40], ax $sequence_7 = { 48897018 48897820 4156 33ed 4c8d35e6900000 448bd5 488bf1 } // n = 7, score = 100 // 48897018 | inc esp // 48897820 | mov dword ptr [esp + 0x48], ebp // 4156 | inc ecx // 33ed | lea eax, [ebp - 1] // 4c8d35e6900000 | movzx ecx, byte ptr [edx + eax*4 + 0x13fd2] // 448bd5 | movzx esi, byte ptr [edx + eax*4 + 0x13fd3] // 488bf1 | mov ebx, ecx $sequence_8 = { e8???????? 488bd7 4c8d05fecd0000 83e23f } // n = 4, score = 100 // e8???????? | // 488bd7 | dec esp // 4c8d05fecd0000 | add ecx, eax // 83e23f | dec ecx $sequence_9 = { 488bda 4c8d0d6bad0000 8bf9 488d15a2930000 b906000000 } // n = 5, score = 100 // 488bda | mov dword ptr [ebx + 0x48], ecx // 4c8d0d6bad0000 | dec eax // 8bf9 | arpl di, bx // 488d15a2930000 | dec eax // b906000000 | lea ecx, [0x14070] condition: 7 of them and filesize < 364544 }
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