Actor(s): Lazarus Group
There is no description at this point.
rule win_sierras_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.sierras." 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.sierras" 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 = { 8d542408 8d442410 52 6a00 } // n = 4, score = 200 // 8d542408 | lea edx, [esp + 8] // 8d442410 | lea eax, [esp + 0x10] // 52 | push edx // 6a00 | push 0 $sequence_1 = { 81c474010000 c21000 6a6d 56 } // n = 4, score = 200 // 81c474010000 | add esp, 0x174 // c21000 | ret 0x10 // 6a6d | push 0x6d // 56 | push esi $sequence_2 = { 8b45f0 3b4510 72c3 eb62 } // n = 4, score = 200 // 8b45f0 | mov eax, dword ptr [ebp - 0x10] // 3b4510 | cmp eax, dword ptr [ebp + 0x10] // 72c3 | jb 0xffffffc5 // eb62 | jmp 0x64 $sequence_3 = { 3bf8 7cce 8b442418 83c520 40 83f803 89442418 } // n = 7, score = 200 // 3bf8 | cmp edi, eax // 7cce | jl 0xffffffd0 // 8b442418 | mov eax, dword ptr [esp + 0x18] // 83c520 | add ebp, 0x20 // 40 | inc eax // 83f803 | cmp eax, 3 // 89442418 | mov dword ptr [esp + 0x18], eax $sequence_4 = { 8d5060 3beb 7421 8bca 2bc8 8d4429a0 } // n = 6, score = 200 // 8d5060 | lea edx, [eax + 0x60] // 3beb | cmp ebp, ebx // 7421 | je 0x23 // 8bca | mov ecx, edx // 2bc8 | sub ecx, eax // 8d4429a0 | lea eax, [ecx + ebp - 0x60] $sequence_5 = { 8d4e04 8bc6 3bf1 740d } // n = 4, score = 200 // 8d4e04 | lea ecx, [esi + 4] // 8bc6 | mov eax, esi // 3bf1 | cmp esi, ecx // 740d | je 0xf $sequence_6 = { 56 8bf1 e8???????? 8b8610010000 } // n = 4, score = 200 // 56 | push esi // 8bf1 | mov esi, ecx // e8???????? | // 8b8610010000 | mov eax, dword ptr [esi + 0x110] $sequence_7 = { c1fa04 8bc2 c1e81f 03d0 83fa01 0f838a000000 } // n = 6, score = 200 // c1fa04 | sar edx, 4 // 8bc2 | mov eax, edx // c1e81f | shr eax, 0x1f // 03d0 | add edx, eax // 83fa01 | cmp edx, 1 // 0f838a000000 | jae 0x90 $sequence_8 = { 8d4de0 e8???????? 0175f0 017514 03fb 3b7d10 72b0 } // n = 7, score = 200 // 8d4de0 | lea ecx, [ebp - 0x20] // e8???????? | // 0175f0 | add dword ptr [ebp - 0x10], esi // 017514 | add dword ptr [ebp + 0x14], esi // 03fb | add edi, ebx // 3b7d10 | cmp edi, dword ptr [ebp + 0x10] // 72b0 | jb 0xffffffb2 $sequence_9 = { c21800 56 8bf1 57 68???????? } // n = 5, score = 200 // c21800 | ret 0x18 // 56 | push esi // 8bf1 | mov esi, ecx // 57 | push edi // 68???????? | $sequence_10 = { 51 8d542418 68???????? 52 e8???????? 83c41c } // n = 6, score = 200 // 51 | push ecx // 8d542418 | lea edx, [esp + 0x18] // 68???????? | // 52 | push edx // e8???????? | // 83c41c | add esp, 0x1c $sequence_11 = { e8???????? 8b8610010000 5e c3 56 8bf1 } // n = 6, score = 200 // e8???????? | // 8b8610010000 | mov eax, dword ptr [esi + 0x110] // 5e | pop esi // c3 | ret // 56 | push esi // 8bf1 | mov esi, ecx $sequence_12 = { 730d 391488 7403 41 } // n = 4, score = 200 // 730d | jae 0xf // 391488 | cmp dword ptr [eax + ecx*4], edx // 7403 | je 5 // 41 | inc ecx $sequence_13 = { 72c3 eb62 837d1000 8d5ef8 7656 8b4514 894514 } // n = 7, score = 200 // 72c3 | jb 0xffffffc5 // eb62 | jmp 0x64 // 837d1000 | cmp dword ptr [ebp + 0x10], 0 // 8d5ef8 | lea ebx, [esi - 8] // 7656 | jbe 0x58 // 8b4514 | mov eax, dword ptr [ebp + 0x14] // 894514 | mov dword ptr [ebp + 0x14], eax $sequence_14 = { c706???????? 50 ff15???????? 8d4e04 e8???????? 5e c3 } // n = 7, score = 200 // c706???????? | // 50 | push eax // ff15???????? | // 8d4e04 | lea ecx, [esi + 4] // e8???????? | // 5e | pop esi // c3 | ret $sequence_15 = { 8bf1 c706???????? e8???????? 8b7608 } // n = 4, score = 200 // 8bf1 | mov esi, ecx // c706???????? | // e8???????? | // 8b7608 | mov esi, dword ptr [esi + 8] condition: 7 of them and filesize < 131072 }
import "pe" rule win_sierras_w0 { meta: copyright = "2015 Novetta Solutions" author = "Novetta Threat Research & Interdiction Group - trig@novetta.com" info = "charlie component" hash = "f4750e1d82b08318bdc1eb6d3399dee52750250f7959a5e4f83245449f399698" source = "https://github.com/mattulm/sfiles_yara/blob/master/malware/SierraCharlie.yar" malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.sierras" malpedia_version = "20170517" malpedia_license = "CC BY-NC-SA 4.0" malpedia_sharing = "TLP:WHITE" strings: /* 8B 0D 50 A7 56 00 mov ecx, DnsFree 81 F6 8C 3F 7C 5E xor esi, 5E7C3F8Ch 6A 01 push 1 ; _DWORD 50 push eax ; _DWORD 85 C9 test ecx, ecx 74 3A jz short loc_40580B FF D1 call ecx ; DnsFree */ $dnsResolve = { 8B 0D 50 A7 56 00 81 F6 8C 3F 7C 5E 6A 01 50 85 C9 74 3A FF D1 } $file1 = "wmplog21t.sqm" $file2 = "wmplog15r.sqm" $file3 = "wmplog09c.sqm" condition: $dnsResolve in ((pe.sections[pe.section_index(".text")].raw_data_offset)..(pe.sections[pe.section_index(".text")].raw_data_offset + pe.sections[pe.section_index(".text")].raw_data_size)) or 2 of ($file*) }
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