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 = "2026-05-04" 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 = "20260422" malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14" malpedia_version = "20260504" 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 = { c3 56 8bf1 e8???????? 8d8614010000 5e } // n = 6, score = 200 // c3 | ret // 56 | push esi // 8bf1 | mov esi, ecx // e8???????? | // 8d8614010000 | lea eax, [esi + 0x114] // 5e | pop esi $sequence_1 = { 8b45f0 3b4510 72c3 eb62 837d1000 8d5ef8 7656 } // n = 7, score = 200 // 8b45f0 | mov eax, dword ptr [ebp - 0x10] // 3b4510 | cmp eax, dword ptr [ebp + 0x10] // 72c3 | jb 0xffffffc5 // eb62 | jmp 0x64 // 837d1000 | cmp dword ptr [ebp + 0x10], 0 // 8d5ef8 | lea ebx, [esi - 8] // 7656 | jbe 0x58 $sequence_2 = { 52 6a00 ffd6 8d842428020000 } // n = 4, score = 200 // 52 | push edx // 6a00 | push 0 // ffd6 | call esi // 8d842428020000 | lea eax, [esp + 0x228] $sequence_3 = { 7202 8bc3 837d0800 50 } // n = 4, score = 200 // 7202 | jb 4 // 8bc3 | mov eax, ebx // 837d0800 | cmp dword ptr [ebp + 8], 0 // 50 | push eax $sequence_4 = { 89442414 8d44240c 50 6a02 56 c744243401000000 } // n = 6, score = 200 // 89442414 | mov dword ptr [esp + 0x14], eax // 8d44240c | lea eax, [esp + 0xc] // 50 | push eax // 6a02 | push 2 // 56 | push esi // c744243401000000 | mov dword ptr [esp + 0x34], 1 $sequence_5 = { e8???????? 83c430 683f000f00 6a00 6a00 } // n = 5, score = 200 // e8???????? | // 83c430 | add esp, 0x30 // 683f000f00 | push 0xf003f // 6a00 | push 0 // 6a00 | push 0 $sequence_6 = { e8???????? 68???????? a3???????? 66c705????????901f e8???????? } // n = 5, score = 200 // e8???????? | // 68???????? | // a3???????? | // 66c705????????901f | // e8???????? | $sequence_7 = { ffd6 e8???????? 85c0 7524 8b35???????? 68???????? } // n = 6, score = 200 // ffd6 | call esi // e8???????? | // 85c0 | test eax, eax // 7524 | jne 0x26 // 8b35???????? | // 68???????? | $sequence_8 = { 68???????? 8d8608020000 50 ff15???????? 8bf8 } // n = 5, score = 200 // 68???????? | // 8d8608020000 | lea eax, [esi + 0x208] // 50 | push eax // ff15???????? | // 8bf8 | mov edi, eax $sequence_9 = { e8???????? 6a00 56 ff7514 8d4de0 e8???????? } // n = 6, score = 200 // e8???????? | // 6a00 | push 0 // 56 | push esi // ff7514 | push dword ptr [ebp + 0x14] // 8d4de0 | lea ecx, [ebp - 0x20] // e8???????? | $sequence_10 = { 83f81c 0f87e4100000 ff24851b574000 8b4608 } // n = 4, score = 200 // 83f81c | cmp eax, 0x1c // 0f87e4100000 | ja 0x10ea // ff24851b574000 | jmp dword ptr [eax*4 + 0x40571b] // 8b4608 | mov eax, dword ptr [esi + 8] $sequence_11 = { 8bce c1e907 0fb689d4924000 8bf9 } // n = 4, score = 200 // 8bce | mov ecx, esi // c1e907 | shr ecx, 7 // 0fb689d4924000 | movzx ecx, byte ptr [ecx + 0x4092d4] // 8bf9 | mov edi, ecx $sequence_12 = { 50 6a00 57 e8???????? 85c0 750d ff15???????? } // n = 7, score = 200 // 50 | push eax // 6a00 | push 0 // 57 | push edi // e8???????? | // 85c0 | test eax, eax // 750d | jne 0xf // ff15???????? | $sequence_13 = { 8bcb 56 8bb42410040000 8bc1 } // n = 4, score = 200 // 8bcb | mov ecx, ebx // 56 | push esi // 8bb42410040000 | mov esi, dword ptr [esp + 0x410] // 8bc1 | mov eax, ecx $sequence_14 = { 897dfc 0f8cc0000000 837d0801 7e58 837d0803 } // n = 5, score = 200 // 897dfc | mov dword ptr [ebp - 4], edi // 0f8cc0000000 | jl 0xc6 // 837d0801 | cmp dword ptr [ebp + 8], 1 // 7e58 | jle 0x5a // 837d0803 | cmp dword ptr [ebp + 8], 3 $sequence_15 = { 735b 83ff03 7330 837df800 0f842b080000 8b45fc } // n = 6, score = 200 // 735b | jae 0x5d // 83ff03 | cmp edi, 3 // 7330 | jae 0x32 // 837df800 | cmp dword ptr [ebp - 8], 0 // 0f842b080000 | je 0x831 // 8b45fc | mov eax, dword ptr [ebp - 4] 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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