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 = "2026-05-04" 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 = "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 = { 25ffffff00 0d00000005 e9???????? 8bd7 397b1c 7640 } // n = 6, score = 1600 // 25ffffff00 | and eax, 0xffffff // 0d00000005 | or eax, 0x5000000 // e9???????? | // 8bd7 | mov edx, edi // 397b1c | cmp dword ptr [ebx + 0x1c], edi // 7640 | jbe 0x42 $sequence_1 = { 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_2 = { 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_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 = { 33ff 8bf7 8d6f10 ff15???????? 0f31 } // n = 5, score = 1600 // 33ff | xor edi, edi // 8bf7 | mov esi, edi // 8d6f10 | lea ebp, [edi + 0x10] // ff15???????? | // 0f31 | rdtsc $sequence_5 = { 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_6 = { e8???????? 85c0 7512 ff15???????? 25ffffff00 0d00000003 } // n = 6, score = 1500 // e8???????? | // 85c0 | mov dword ptr [edi + 0xc], ebx // 7512 | mov eax, 0x40000000 // ff15???????? | // 25ffffff00 | cpuid // 0d00000003 | mov dword ptr [edi + 0xc], ebx $sequence_7 = { 7417 448bc2 0f31 48c1e220 480bc2 } // n = 5, score = 1500 // 7417 | mov dword ptr [edi + 4], eax // 448bc2 | xor ecx, ecx // 0f31 | mov eax, 0x40000000 // 48c1e220 | cpuid // 480bc2 | mov dword ptr [edi + 4], eax $sequence_8 = { 4c03da 4585c0 7420 498d4b10 f7411400000020 } // n = 5, score = 1500 // 4c03da | and eax, 0xffffff // 4585c0 | dec esp // 7420 | add ebx, edx // 498d4b10 | inc ebp // f7411400000020 | test eax, eax $sequence_9 = { 488bcd ffd0 ff15???????? 25ffffff00 } // n = 4, score = 1500 // 488bcd | dec eax // ffd0 | mov ecx, ebp // ff15???????? | // 25ffffff00 | call eax $sequence_10 = { 7512 ff15???????? 25ffffff00 0d00000007 eb4a 397b1c 7629 } // n = 7, score = 1500 // 7512 | cmp dword ptr [ebx + 0x1c], edi // ff15???????? | // 25ffffff00 | cpuid // 0d00000007 | mov dword ptr [edi + 4], eax // eb4a | xor ecx, ecx // 397b1c | mov eax, 0x40000000 // 7629 | cpuid $sequence_11 = { 55 33ed c744241804000000 56 } // n = 4, score = 200 // 55 | mov esi, eax // 33ed | lea ebp, [esp + 0x10] // c744241804000000 | xor ecx, ecx // 56 | mov eax, 0x80000001 $sequence_12 = { 7461 8d4c2410 51 8d4c2424 51 53 } // n = 6, score = 200 // 7461 | lea eax, [esi + 1] // 8d4c2410 | jne 0xffffff9c // 51 | push eax // 8d4c2424 | push ecx // 51 | push ebx // 53 | push ebp $sequence_13 = { 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 | inc esp // 8d4601 | mov eax, edx $sequence_14 = { 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_15 = { 03f8 8d0c7b e8???????? 03f8 } // n = 4, score = 200 // 03f8 | rol al, 3 // 8d0c7b | movzx ecx, al // e8???????? | // 03f8 | mov eax, ecx $sequence_16 = { 8bf9 33f6 33c9 0fa2 894500 } // n = 5, score = 200 // 8bf9 | add edi, eax // 33f6 | lea ecx, [ebx + edi*2] // 33c9 | add edi, eax // 0fa2 | jne 6 // 894500 | mov dword ptr [edi], eax $sequence_17 = { 7504 8907 8bf0 8d6c2410 33c9 b801000080 } // n = 6, score = 200 // 7504 | and ecx, 0xf // 8907 | mov dword ptr [esp + 0x14], esi // 8bf0 | jmp 0x21 // 8d6c2410 | lea eax, [ecx + 1] // 33c9 | mov dword ptr [esp + 0x14], esi // b801000080 | mov dword ptr [esp + 0x10], eax condition: 7 of them and filesize < 107520 }
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