Actor(s): Tiny Spider
There is no description at this point.
rule win_tinyloader_auto { meta: author = "Felix Bilstein - yara-signator at cocacoding dot com" date = "2022-04-08" version = "1" description = "Detects win.tinyloader." 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.tinyloader" malpedia_rule_date = "20220405" malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a" malpedia_version = "20220411" 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 = { 83f8ff 7505 e9???????? 8b4500 83c008 c70000000000 c7855808000000000000 } // n = 7, score = 100 // 83f8ff | cmp eax, -1 // 7505 | jne 7 // e9???????? | // 8b4500 | mov eax, dword ptr [ebp] // 83c008 | add eax, 8 // c70000000000 | mov dword ptr [eax], 0 // c7855808000000000000 | mov dword ptr [ebp + 0x858], 0 $sequence_1 = { 6832a00000 ff15???????? 8b9da8050000 66894302 } // n = 4, score = 100 // 6832a00000 | push 0xa032 // ff15???????? | // 8b9da8050000 | mov ebx, dword ptr [ebp + 0x5a8] // 66894302 | mov word ptr [ebx + 2], ax $sequence_2 = { 31db 90 31c9 90 } // n = 4, score = 100 // 31db | xor ebx, ebx // 90 | nop // 31c9 | xor ecx, ecx // 90 | nop $sequence_3 = { e9???????? 8b5d00 81c300040000 6a00 ff33 ff7500 } // n = 6, score = 100 // e9???????? | // 8b5d00 | mov ebx, dword ptr [ebp] // 81c300040000 | add ebx, 0x400 // 6a00 | push 0 // ff33 | push dword ptr [ebx] // ff7500 | push dword ptr [ebp] $sequence_4 = { ff15???????? 8d9d40050000 53 50 } // n = 4, score = 100 // ff15???????? | // 8d9d40050000 | lea ebx, dword ptr [ebp + 0x540] // 53 | push ebx // 50 | push eax $sequence_5 = { ff15???????? 8d3500304000 89c7 53 31c9 49 89ca } // n = 7, score = 100 // ff15???????? | // 8d3500304000 | lea esi, dword ptr [0x403000] // 89c7 | mov edi, eax // 53 | push ebx // 31c9 | xor ecx, ecx // 49 | dec ecx // 89ca | mov edx, ecx $sequence_6 = { ff15???????? e8???????? 7368 656c 6c } // n = 5, score = 100 // ff15???????? | // e8???????? | // 7368 | jae 0x6a // 656c | insb byte ptr es:[edi], dx // 6c | insb byte ptr es:[edi], dx $sequence_7 = { 31db 31c9 31d2 8b4d00 8b4904 8b5500 } // n = 6, score = 100 // 31db | xor ebx, ebx // 31c9 | xor ecx, ecx // 31d2 | xor edx, edx // 8b4d00 | mov ecx, dword ptr [ebp] // 8b4904 | mov ecx, dword ptr [ecx + 4] // 8b5500 | mov edx, dword ptr [ebp] $sequence_8 = { 90 31db 90 90 8bbb97114000 90 8938 } // n = 7, score = 100 // 90 | nop // 31db | xor ebx, ebx // 90 | nop // 90 | nop // 8bbb97114000 | mov edi, dword ptr [ebx + 0x401197] // 90 | nop // 8938 | mov dword ptr [eax], edi $sequence_9 = { 8b5d00 66894308 6a10 ffb5a8050000 } // n = 4, score = 100 // 8b5d00 | mov ebx, dword ptr [ebp] // 66894308 | mov word ptr [ebx + 8], ax // 6a10 | push 0x10 // ffb5a8050000 | push dword ptr [ebp + 0x5a8] $sequence_10 = { 8b4308 83f800 7407 807c03ffc3 7402 eb42 } // n = 6, score = 100 // 8b4308 | mov eax, dword ptr [ebx + 8] // 83f800 | cmp eax, 0 // 7407 | je 9 // 807c03ffc3 | cmp byte ptr [ebx + eax - 1], 0xc3 // 7402 | je 4 // eb42 | jmp 0x44 $sequence_11 = { 8985b0020000 83bdb002000000 7502 eb1f ff15???????? 8d9d40050000 } // n = 6, score = 100 // 8985b0020000 | mov dword ptr [ebp + 0x2b0], eax // 83bdb002000000 | cmp dword ptr [ebp + 0x2b0], 0 // 7502 | jne 4 // eb1f | jmp 0x21 // ff15???????? | // 8d9d40050000 | lea ebx, dword ptr [ebp + 0x540] $sequence_12 = { 6a40 6800300000 6800800200 6a00 ff15???????? 90 8b1d???????? } // n = 7, score = 100 // 6a40 | push 0x40 // 6800300000 | push 0x3000 // 6800800200 | push 0x28000 // 6a00 | push 0 // ff15???????? | // 90 | nop // 8b1d???????? | $sequence_13 = { 8998f8070000 90 8b1d???????? 90 895830 } // n = 5, score = 100 // 8998f8070000 | mov dword ptr [eax + 0x7f8], ebx // 90 | nop // 8b1d???????? | // 90 | nop // 895830 | mov dword ptr [eax + 0x30], ebx $sequence_14 = { 89c6 90 0500400100 90 31db } // n = 5, score = 100 // 89c6 | mov esi, eax // 90 | nop // 0500400100 | add eax, 0x14000 // 90 | nop // 31db | xor ebx, ebx $sequence_15 = { 740e 83fb00 7509 90 3108 90 41 } // n = 7, score = 100 // 740e | je 0x10 // 83fb00 | cmp ebx, 0 // 7509 | jne 0xb // 90 | nop // 3108 | xor dword ptr [eax], ecx // 90 | nop // 41 | inc ecx condition: 7 of them and filesize < 40960 }
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