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 = "2023-12-06" 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 = "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 = { f3a4 8d8c2424050000 8d942430080000 51 } // n = 4, score = 200 // f3a4 | rep movsb byte ptr es:[edi], byte ptr [esi] // 8d8c2424050000 | lea ecx, [esp + 0x524] // 8d942430080000 | lea edx, [esp + 0x830] // 51 | push ecx $sequence_1 = { 56 8bf1 57 68???????? 8d4604 50 } // n = 6, score = 200 // 56 | push esi // 8bf1 | mov esi, ecx // 57 | push edi // 68???????? | // 8d4604 | lea eax, [esi + 4] // 50 | push eax $sequence_2 = { 50 8d45e0 50 e8???????? eb0f 8b4dec } // n = 6, score = 200 // 50 | push eax // 8d45e0 | lea eax, [ebp - 0x20] // 50 | push eax // e8???????? | // eb0f | jmp 0x11 // 8b4dec | mov ecx, dword ptr [ebp - 0x14] $sequence_3 = { e8???????? 50 8d442430 50 8d8c24ec000000 } // n = 5, score = 200 // e8???????? | // 50 | push eax // 8d442430 | lea eax, [esp + 0x30] // 50 | push eax // 8d8c24ec000000 | lea ecx, [esp + 0xec] $sequence_4 = { 0f8480030000 8b4dfc ff4df8 0fb611 8bcf } // n = 5, score = 200 // 0f8480030000 | je 0x386 // 8b4dfc | mov ecx, dword ptr [ebp - 4] // ff4df8 | dec dword ptr [ebp - 8] // 0fb611 | movzx edx, byte ptr [ecx] // 8bcf | mov ecx, edi $sequence_5 = { 7507 e8???????? eb05 e8???????? 0175f0 } // n = 5, score = 200 // 7507 | jne 9 // e8???????? | // eb05 | jmp 7 // e8???????? | // 0175f0 | add dword ptr [ebp - 0x10], esi $sequence_6 = { 8bf1 e8???????? 8b8698010000 5e } // n = 4, score = 200 // 8bf1 | mov esi, ecx // e8???????? | // 8b8698010000 | mov eax, dword ptr [esi + 0x198] // 5e | pop esi $sequence_7 = { 8bc8 83e103 f3a4 8bbc2410040000 } // n = 4, score = 200 // 8bc8 | mov ecx, eax // 83e103 | and ecx, 3 // f3a4 | rep movsb byte ptr es:[edi], byte ptr [esi] // 8bbc2410040000 | mov edi, dword ptr [esp + 0x410] $sequence_8 = { 03fb 3b7d10 72b0 8b5df0 834dfcff 8d4de0 } // n = 6, score = 200 // 03fb | add edi, ebx // 3b7d10 | cmp edi, dword ptr [ebp + 0x10] // 72b0 | jb 0xffffffb2 // 8b5df0 | mov ebx, dword ptr [ebp - 0x10] // 834dfcff | or dword ptr [ebp - 4], 0xffffffff // 8d4de0 | lea ecx, [ebp - 0x20] $sequence_9 = { 8bf1 33db 6a01 6a78 } // n = 4, score = 200 // 8bf1 | mov esi, ecx // 33db | xor ebx, ebx // 6a01 | push 1 // 6a78 | push 0x78 $sequence_10 = { f2ae f7d1 2bf9 8d942480000000 8bf7 8bd9 8bfa } // n = 7, score = 200 // f2ae | repne scasb al, byte ptr es:[edi] // f7d1 | not ecx // 2bf9 | sub edi, ecx // 8d942480000000 | lea edx, [esp + 0x80] // 8bf7 | mov esi, edi // 8bd9 | mov ebx, ecx // 8bfa | mov edi, edx $sequence_11 = { 8bf1 e8???????? 8b8608010000 5e c3 56 } // n = 6, score = 200 // 8bf1 | mov esi, ecx // e8???????? | // 8b8608010000 | mov eax, dword ptr [esi + 0x108] // 5e | pop esi // c3 | ret // 56 | push esi $sequence_12 = { 397d08 897dfc 0f8cc0000000 837d0801 7e58 } // n = 5, score = 200 // 397d08 | cmp dword ptr [ebp + 8], edi // 897dfc | mov dword ptr [ebp - 4], edi // 0f8cc0000000 | jl 0xc6 // 837d0801 | cmp dword ptr [ebp + 8], 1 // 7e58 | jle 0x5a $sequence_13 = { c7401880dd4000 e9???????? 83e00f c70613000000 894648 8b4648 85c0 } // n = 7, score = 200 // c7401880dd4000 | mov dword ptr [eax + 0x18], 0x40dd80 // e9???????? | // 83e00f | and eax, 0xf // c70613000000 | mov dword ptr [esi], 0x13 // 894648 | mov dword ptr [esi + 0x48], eax // 8b4648 | mov eax, dword ptr [esi + 0x48] // 85c0 | test eax, eax $sequence_14 = { 58 0fb688c88c4000 6683bc8e7e0a000000 7506 } // n = 4, score = 200 // 58 | pop eax // 0fb688c88c4000 | movzx ecx, byte ptr [eax + 0x408cc8] // 6683bc8e7e0a000000 | cmp word ptr [esi + ecx*4 + 0xa7e], 0 // 7506 | jne 8 $sequence_15 = { 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 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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