Actor(s): Greenbug, APT34
There is no description at this point.
rule win_ismagent_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-05-04" version = "1" description = "Detects win.ismagent." 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.ismagent" 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 = { 8816 eb3e c6060d 8b048d48404200 8854382a eb2e } // n = 6, score = 200 // 8816 | mov byte ptr [esi], dl // eb3e | jmp 0x40 // c6060d | mov byte ptr [esi], 0xd // 8b048d48404200 | mov eax, dword ptr [ecx*4 + 0x424048] // 8854382a | mov byte ptr [eax + edi + 0x2a], dl // eb2e | jmp 0x30 $sequence_1 = { 8b048d48404200 5b 8b543818 8955ec } // n = 4, score = 200 // 8b048d48404200 | mov eax, dword ptr [ecx*4 + 0x424048] // 5b | pop ebx // 8b543818 | mov edx, dword ptr [eax + edi + 0x18] // 8955ec | mov dword ptr [ebp - 0x14], edx $sequence_2 = { 8bd7 2bd1 8a01 8d4901 884411ff 84c0 } // n = 6, score = 200 // 8bd7 | mov edx, edi // 2bd1 | sub edx, ecx // 8a01 | mov al, byte ptr [ecx] // 8d4901 | lea ecx, [ecx + 1] // 884411ff | mov byte ptr [ecx + edx - 1], al // 84c0 | test al, al $sequence_3 = { 6a44 83e103 6a00 f3a4 50 e8???????? 8b7c244c } // n = 7, score = 200 // 6a44 | push 0x44 // 83e103 | and ecx, 3 // 6a00 | push 0 // f3a4 | rep movsb byte ptr es:[edi], byte ptr [esi] // 50 | push eax // e8???????? | // 8b7c244c | mov edi, dword ptr [esp + 0x4c] $sequence_4 = { c1f806 6bc930 8b048548404200 f644082801 7406 8b440818 } // n = 6, score = 200 // c1f806 | sar eax, 6 // 6bc930 | imul ecx, ecx, 0x30 // 8b048548404200 | mov eax, dword ptr [eax*4 + 0x424048] // f644082801 | test byte ptr [eax + ecx + 0x28], 1 // 7406 | je 8 // 8b440818 | mov eax, dword ptr [eax + ecx + 0x18] $sequence_5 = { 53 8b5d10 8b048548404200 56 8b7508 57 8b4c0818 } // n = 7, score = 200 // 53 | push ebx // 8b5d10 | mov ebx, dword ptr [ebp + 0x10] // 8b048548404200 | mov eax, dword ptr [eax*4 + 0x424048] // 56 | push esi // 8b7508 | mov esi, dword ptr [ebp + 8] // 57 | push edi // 8b4c0818 | mov ecx, dword ptr [eax + ecx + 0x18] $sequence_6 = { 8a01 41 84c0 75f9 2bca 0f8417010000 8d8424500b0000 } // n = 7, score = 200 // 8a01 | mov al, byte ptr [ecx] // 41 | inc ecx // 84c0 | test al, al // 75f9 | jne 0xfffffffb // 2bca | sub ecx, edx // 0f8417010000 | je 0x11d // 8d8424500b0000 | lea eax, [esp + 0xb50] $sequence_7 = { 47 42 8d7001 90 8a08 40 } // n = 6, score = 200 // 47 | inc edi // 42 | inc edx // 8d7001 | lea esi, [eax + 1] // 90 | nop // 8a08 | mov cl, byte ptr [eax] // 40 | inc eax condition: 7 of them and filesize < 327680 }
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