rule win_tinyloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        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 = "20230328"
        malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d"
        malpedia_version = "20230407"
        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 = { 8b4500 83c00c ffd0 31db }
            // n = 4, score = 100
            //   8b4500               | mov                 eax, dword ptr [ebp]
            //   83c00c               | add                 eax, 0xc
            //   ffd0                 | call                eax
            //   31db                 | xor                 ebx, ebx

        $sequence_1 = { 68???????? ff15???????? 8d3500304000 89c7 }
            // n = 4, score = 100
            //   68????????           |                     
            //   ff15????????         |                     
            //   8d3500304000         | lea                 esi, [0x403000]
            //   89c7                 | mov                 edi, eax

        $sequence_2 = { ff15???????? e8???????? 53 68656c6c45 7865 637574 6541 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   e8????????           |                     
            //   53                   | push                ebx
            //   68656c6c45           | push                0x456c6c65
            //   7865                 | js                  0x67
            //   637574               | arpl                word ptr [ebp + 0x74], si
            //   6541                 | inc                 ecx

        $sequence_3 = { 8938 90 81fb04030000 730d 90 }
            // n = 5, score = 100
            //   8938                 | mov                 dword ptr [eax], edi
            //   90                   | nop                 
            //   81fb04030000         | cmp                 ebx, 0x304
            //   730d                 | jae                 0xf
            //   90                   | nop                 

        $sequence_4 = { 8b1d???????? 90 895838 90 89c6 90 0500400100 }
            // n = 7, score = 100
            //   8b1d????????         |                     
            //   90                   | nop                 
            //   895838               | mov                 dword ptr [eax + 0x38], ebx
            //   90                   | nop                 
            //   89c6                 | mov                 esi, eax
            //   90                   | nop                 
            //   0500400100           | add                 eax, 0x14000

        $sequence_5 = { 7505 e9???????? 8b4500 83c008 c70000000000 }
            // n = 5, score = 100
            //   7505                 | jne                 7
            //   e9????????           |                     
            //   8b4500               | mov                 eax, dword ptr [ebp]
            //   83c008               | add                 eax, 8
            //   c70000000000         | mov                 dword ptr [eax], 0

        $sequence_6 = { 8b03 8b5d00 66894308 6a10 ffb5a8050000 ffb5b8050000 }
            // n = 6, score = 100
            //   8b03                 | mov                 eax, dword ptr [ebx]
            //   8b5d00               | mov                 ebx, dword ptr [ebp]
            //   66894308             | mov                 word ptr [ebx + 8], ax
            //   6a10                 | push                0x10
            //   ffb5a8050000         | push                dword ptr [ebp + 0x5a8]
            //   ffb5b8050000         | push                dword ptr [ebp + 0x5b8]

        $sequence_7 = { 637574 6541 0050ff 15???????? c705????????00010000 }
            // n = 5, score = 100
            //   637574               | arpl                word ptr [ebp + 0x74], si
            //   6541                 | inc                 ecx
            //   0050ff               | add                 byte ptr [eax - 1], dl
            //   15????????           |                     
            //   c705????????00010000     |     

        $sequence_8 = { 6a00 6800040000 53 ffb5b8050000 ff15???????? }
            // n = 5, score = 100
            //   6a00                 | push                0
            //   6800040000           | push                0x400
            //   53                   | push                ebx
            //   ffb5b8050000         | push                dword ptr [ebp + 0x5b8]
            //   ff15????????         |                     

        $sequence_9 = { ff15???????? 8b9da8050000 66894302 66c7030200 e8???????? }
            // n = 5, score = 100
            //   ff15????????         |                     
            //   8b9da8050000         | mov                 ebx, dword ptr [ebp + 0x5a8]
            //   66894302             | mov                 word ptr [ebx + 2], ax
            //   66c7030200           | mov                 word ptr [ebx], 2
            //   e8????????           |                     

        $sequence_10 = { 8985b0020000 83bdb002000000 7502 eb1f ff15???????? }
            // n = 5, score = 100
            //   8985b0020000         | mov                 dword ptr [ebp + 0x2b0], eax
            //   83bdb002000000       | cmp                 dword ptr [ebp + 0x2b0], 0
            //   7502                 | jne                 4
            //   eb1f                 | jmp                 0x21
            //   ff15????????         |                     

        $sequence_11 = { 8b5500 01da 83c20c 310a 3b8558080000 }
            // n = 5, score = 100
            //   8b5500               | mov                 edx, dword ptr [ebp]
            //   01da                 | add                 edx, ebx
            //   83c20c               | add                 edx, 0xc
            //   310a                 | xor                 dword ptr [edx], ecx
            //   3b8558080000         | cmp                 eax, dword ptr [ebp + 0x858]

        $sequence_12 = { 0500200000 8985a8050000 0500080000 894508 }
            // n = 4, score = 100
            //   0500200000           | add                 eax, 0x2000
            //   8985a8050000         | mov                 dword ptr [ebp + 0x5a8], eax
            //   0500080000           | add                 eax, 0x800
            //   894508               | mov                 dword ptr [ebp + 8], eax

        $sequence_13 = { ff15???????? 90 8b1d???????? 90 8998f8070000 }
            // n = 5, score = 100
            //   ff15????????         |                     
            //   90                   | nop                 
            //   8b1d????????         |                     
            //   90                   | nop                 
            //   8998f8070000         | mov                 dword ptr [eax + 0x7f8], ebx

        $sequence_14 = { 3108 90 813890909090 740e }
            // n = 4, score = 100
            //   3108                 | xor                 dword ptr [eax], ecx
            //   90                   | nop                 
            //   813890909090         | cmp                 dword ptr [eax], 0x90909090
            //   740e                 | je                  0x10

        $sequence_15 = { 83fb00 7509 90 3108 }
            // n = 4, score = 100
            //   83fb00               | cmp                 ebx, 0
            //   7509                 | jne                 0xb
            //   90                   | nop                 
            //   3108                 | xor                 dword ptr [eax], ecx

    condition:
        7 of them and filesize < 40960
}