A loader used to deliver IcedID, fetching a fake image from which payloads are extracted.
rule win_photoloader_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2026-09-17" version = "1" description = "Detects win.photoloader." 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.photoloader" 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 = { ff15???????? 25ffffff00 0d00000005 e9???????? 8bd7 397b1c } // n = 6, score = 1600 // ff15???????? | // 25ffffff00 | and eax, 0xffffff // 0d00000005 | or eax, 0x5000000 // e9???????? | // 8bd7 | mov edx, edi // 397b1c | cmp dword ptr [ebx + 0x1c], edi $sequence_1 = { 0fa2 894704 33c9 b800000040 } // n = 4, score = 1600 // 0fa2 | cpuid // 894704 | mov dword ptr [edi + 4], eax // 33c9 | xor ecx, ecx // b800000040 | mov eax, 0x40000000 $sequence_2 = { f7411400000020 7407 8b41f8 3901 } // n = 4, score = 1600 // f7411400000020 | test dword ptr [ecx + 0x14], 0x20000000 // 7407 | je 9 // 8b41f8 | mov eax, dword ptr [ecx - 8] // 3901 | cmp dword ptr [ecx], eax $sequence_3 = { 33c9 b800000040 0fa2 895f0c } // n = 4, score = 1600 // 33c9 | xor ecx, ecx // b800000040 | mov eax, 0x40000000 // 0fa2 | cpuid // 895f0c | mov dword ptr [edi + 0xc], ebx $sequence_4 = { c0c003 0fb6c8 8bc1 83e10f } // n = 4, score = 1600 // c0c003 | rol al, 3 // 0fb6c8 | movzx ecx, al // 8bc1 | mov eax, ecx // 83e10f | and ecx, 0xf $sequence_5 = { 8bf7 8d6f10 ff15???????? 0f31 } // n = 4, score = 1600 // 8bf7 | mov esi, edi // 8d6f10 | lea ebp, [edi + 0x10] // ff15???????? | // 0f31 | rdtsc $sequence_6 = { b90b010000 66394a18 8d41ed 448d59fd 440f44d8 4533c9 } // n = 6, score = 1500 // b90b010000 | cpuid // 66394a18 | mov dword ptr [edi + 0xc], ebx // 8d41ed | mov dword ptr [edi + 4], eax // 448d59fd | xor ecx, ecx // 440f44d8 | mov eax, 0x40000000 // 4533c9 | cpuid $sequence_7 = { 4883ec28 ff15???????? 488bc8 48b877be9f1a2fdd2406 48f7e1 482bca } // n = 6, score = 1500 // 4883ec28 | dec eax // ff15???????? | // 488bc8 | sub esp, 0x28 // 48b877be9f1a2fdd2406 | dec eax // 48f7e1 | mov ecx, eax // 482bca | dec eax $sequence_8 = { 85c0 7512 ff15???????? 25ffffff00 0d00000003 } // n = 5, score = 1500 // 85c0 | cpuid // 7512 | mov dword ptr [edi + 4], eax // ff15???????? | // 25ffffff00 | xor ecx, ecx // 0d00000003 | mov eax, 0x40000000 $sequence_9 = { e8???????? 488d97c6020000 4c8bc5 4803d6 488bcb 488b5c2430 } // n = 6, score = 1500 // e8???????? | // 488d97c6020000 | mov eax, 0x1a9fbe77 // 4c8bc5 | das // 4803d6 | frstor dword ptr [esi + eax] // 488bcb | dec eax // 488b5c2430 | mul ecx $sequence_10 = { 7511 ff15???????? 25ffffff00 0fbae819 } // n = 4, score = 1500 // 7511 | mov edx, edi // ff15???????? | // 25ffffff00 | cmp dword ptr [ebx + 0x1c], edi // 0fbae819 | jbe 0x47 $sequence_11 = { 8bf9 33f6 33c9 0fa2 894500 } // n = 5, score = 200 // 8bf9 | mov dword ptr [esp + 0x14], esi // 33f6 | jmp 0x1d // 33c9 | lea eax, [ecx + 1] // 0fa2 | mov dword ptr [esp + 0x14], esi // 894500 | mov dword ptr [esp + 0x10], eax $sequence_12 = { 03f8 8d0c7b e8???????? 03f8 } // n = 4, score = 200 // 03f8 | dec eax // 8d0c7b | shl edx, 0x20 // e8???????? | // 03f8 | inc edi $sequence_13 = { 7461 8d4c2410 51 8d4c2424 51 53 } // n = 6, score = 200 // 7461 | inc ecx // 8d4c2410 | sub ecx, ecx // 51 | rol al, 3 // 8d4c2424 | movzx ecx, al // 51 | mov eax, ecx // 53 | and ecx, 0xf $sequence_14 = { 89742414 eb1b 8d4101 89742414 89442410 8d4601 } // n = 6, score = 200 // 89742414 | xor ecx, ecx // eb1b | mov eax, 0x40000000 // 8d4101 | cpuid // 89742414 | mov dword ptr [edi + 0xc], ebx // 89442410 | mov esi, edi // 8d4601 | lea ebp, [edi + 0x10] $sequence_15 = { 55 33ed c744241804000000 56 } // n = 4, score = 200 // 55 | lea eax, [esi + 1] // 33ed | jne 0xffffff9c // c744241804000000 | push eax // 56 | push ecx $sequence_16 = { 759a 50 51 53 55 } // n = 5, score = 200 // 759a | rdtsc // 50 | dec eax // 51 | shl edx, 0x20 // 53 | dec eax // 55 | or eax, edx $sequence_17 = { 7504 8907 8bf0 8d6c2410 33c9 b801000080 } // n = 6, score = 200 // 7504 | mov ecx, dword ptr [ebx + edx*8 + 8] // 8907 | dec eax // 8bf0 | or eax, edx // 8d6c2410 | inc ebx // 33c9 | mov ecx, dword ptr [ebx + edx*8 + 0x10] // b801000080 | xor edx, edx condition: 7 of them and filesize < 107520 }
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