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 = "2023-01-25" 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 = "20230124" malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686" malpedia_version = "20230125" 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 = { 29d8 90 31db 90 31c9 } // n = 5, score = 100 // 29d8 | sub eax, ebx // 90 | nop // 31db | xor ebx, ebx // 90 | nop // 31c9 | xor ecx, ecx $sequence_1 = { 8985a8050000 0500080000 894508 0500200000 894518 0500200000 894510 } // n = 7, score = 100 // 8985a8050000 | mov dword ptr [ebp + 0x5a8], eax // 0500080000 | add eax, 0x800 // 894508 | mov dword ptr [ebp + 8], eax // 0500200000 | add eax, 0x2000 // 894518 | mov dword ptr [ebp + 0x18], eax // 0500200000 | add eax, 0x2000 // 894510 | mov dword ptr [ebp + 0x10], eax $sequence_2 = { 81fb04030000 730d 90 83c004 } // n = 4, score = 100 // 81fb04030000 | cmp ebx, 0x304 // 730d | jae 0xf // 90 | nop // 83c004 | add eax, 4 $sequence_3 = { 637574 6541 0050ff 15???????? c705????????00010000 68???????? 68???????? } // n = 7, score = 100 // 637574 | arpl word ptr [ebp + 0x74], si // 6541 | inc ecx // 0050ff | add byte ptr [eax - 1], dl // 15???????? | // c705????????00010000 | // 68???????? | // 68???????? | $sequence_4 = { 0500080000 894520 ffb5a0050000 6802020000 } // n = 4, score = 100 // 0500080000 | add eax, 0x800 // 894520 | mov dword ptr [ebp + 0x20], eax // ffb5a0050000 | push dword ptr [ebp + 0x5a0] // 6802020000 | push 0x202 $sequence_5 = { 90 895830 90 8b1d???????? 90 895838 } // n = 6, score = 100 // 90 | nop // 895830 | mov dword ptr [eax + 0x30], ebx // 90 | nop // 8b1d???????? | // 90 | nop // 895838 | mov dword ptr [eax + 0x38], ebx $sequence_6 = { 7302 ebc3 8b5d00 8b4308 3b8558080000 7402 } // n = 6, score = 100 // 7302 | jae 4 // ebc3 | jmp 0xffffffc5 // 8b5d00 | mov ebx, dword ptr [ebp] // 8b4308 | mov eax, dword ptr [ebx + 8] // 3b8558080000 | cmp eax, dword ptr [ebp + 0x858] // 7402 | je 4 $sequence_7 = { 895838 90 89c6 90 0500400100 } // n = 5, score = 100 // 895838 | mov dword ptr [eax + 0x38], ebx // 90 | nop // 89c6 | mov esi, eax // 90 | nop // 0500400100 | add eax, 0x14000 $sequence_8 = { 8b5510 01da 8b12 8b4500 83c00c } // n = 5, score = 100 // 8b5510 | mov edx, dword ptr [ebp + 0x10] // 01da | add edx, ebx // 8b12 | mov edx, dword ptr [edx] // 8b4500 | mov eax, dword ptr [ebp] // 83c00c | add eax, 0xc $sequence_9 = { ffb5a8050000 ffb5b8050000 ff15???????? 83f8ff 7505 } // n = 5, score = 100 // ffb5a8050000 | push dword ptr [ebp + 0x5a8] // ffb5b8050000 | push dword ptr [ebp + 0x5b8] // ff15???????? | // 83f8ff | cmp eax, -1 // 7505 | jne 7 $sequence_10 = { c131da 4f 75d5 f7d2 f7d1 5b 89d0 } // n = 7, score = 100 // c131da | sal dword ptr [ecx], 0xda // 4f | dec edi // 75d5 | jne 0xffffffd7 // f7d2 | not edx // f7d1 | not ecx // 5b | pop ebx // 89d0 | mov eax, edx $sequence_11 = { 6a00 ff33 ff7500 ffb5b8050000 } // n = 4, score = 100 // 6a00 | push 0 // ff33 | push dword ptr [ebx] // ff7500 | push dword ptr [ebp] // ffb5b8050000 | push dword ptr [ebp + 0x5b8] $sequence_12 = { 90 8998f8070000 90 8b1d???????? 90 895830 } // n = 6, score = 100 // 90 | nop // 8998f8070000 | mov dword ptr [eax + 0x7f8], ebx // 90 | nop // 8b1d???????? | // 90 | nop // 895830 | mov dword ptr [eax + 0x30], ebx $sequence_13 = { 83e80c 39c3 7321 3d80020000 731a 83f800 7615 } // n = 7, score = 100 // 83e80c | sub eax, 0xc // 39c3 | cmp ebx, eax // 7321 | jae 0x23 // 3d80020000 | cmp eax, 0x280 // 731a | jae 0x1c // 83f800 | cmp eax, 0 // 7615 | jbe 0x17 $sequence_14 = { c78540050000000000ba 6a40 6800300000 6800400100 6a00 ff15???????? } // n = 6, score = 100 // c78540050000000000ba | mov dword ptr [ebp + 0x540], 0xba000000 // 6a40 | push 0x40 // 6800300000 | push 0x3000 // 6800400100 | push 0x14000 // 6a00 | push 0 // ff15???????? | $sequence_15 = { 90 8938 90 81fb04030000 } // n = 4, score = 100 // 90 | nop // 8938 | mov dword ptr [eax], edi // 90 | nop // 81fb04030000 | cmp ebx, 0x304 condition: 7 of them and filesize < 40960 }
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