rule win_tinyloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        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 = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 7407 807c03ffc3 7402 eb42 8b4500 }
            // n = 5, score = 100
            //   7407                 | je                  9
            //   807c03ffc3           | cmp                 byte ptr [ebx + eax - 1], 0xc3
            //   7402                 | je                  4
            //   eb42                 | jmp                 0x44
            //   8b4500               | mov                 eax, dword ptr [ebp]

        $sequence_1 = { 90 8938 90 81fb04030000 730d 90 83c004 }
            // n = 7, score = 100
            //   90                   | nop                 
            //   8938                 | mov                 dword ptr [eax], edi
            //   90                   | nop                 
            //   81fb04030000         | cmp                 ebx, 0x304
            //   730d                 | jae                 0xf
            //   90                   | nop                 
            //   83c004               | add                 eax, 4

        $sequence_2 = { ebc3 8b5d00 8b4308 3b8558080000 7402 ebb3 31c0 }
            // n = 7, score = 100
            //   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
            //   ebb3                 | jmp                 0xffffffb5
            //   31c0                 | xor                 eax, eax

        $sequence_3 = { 894518 0500200000 894510 0500080000 894520 ffb5a0050000 }
            // n = 6, score = 100
            //   894518               | mov                 dword ptr [ebp + 0x18], eax
            //   0500200000           | add                 eax, 0x2000
            //   894510               | mov                 dword ptr [ebp + 0x10], eax
            //   0500080000           | add                 eax, 0x800
            //   894520               | mov                 dword ptr [ebp + 0x20], eax
            //   ffb5a0050000         | push                dword ptr [ebp + 0x5a0]

        $sequence_4 = { 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_5 = { 7702 eb28 83e80c 39c3 }
            // n = 4, score = 100
            //   7702                 | ja                  4
            //   eb28                 | jmp                 0x2a
            //   83e80c               | sub                 eax, 0xc
            //   39c3                 | cmp                 ebx, eax

        $sequence_6 = { e8???????? 53 68656c6c45 7865 637574 }
            // n = 5, score = 100
            //   e8????????           |                     
            //   53                   | push                ebx
            //   68656c6c45           | push                0x456c6c65
            //   7865                 | js                  0x67
            //   637574               | arpl                word ptr [ebp + 0x74], si

        $sequence_7 = { 83f8ff 7505 e9???????? 8b5d00 81c300040000 6a00 ff33 }
            // n = 7, score = 100
            //   83f8ff               | cmp                 eax, -1
            //   7505                 | jne                 7
            //   e9????????           |                     
            //   8b5d00               | mov                 ebx, dword ptr [ebp]
            //   81c300040000         | add                 ebx, 0x400
            //   6a00                 | push                0
            //   ff33                 | push                dword ptr [ebx]

        $sequence_8 = { 90 0500400100 90 31db 90 90 8bbb97114000 }
            // n = 7, score = 100
            //   90                   | nop                 
            //   0500400100           | add                 eax, 0x14000
            //   90                   | nop                 
            //   31db                 | xor                 ebx, ebx
            //   90                   | nop                 
            //   90                   | nop                 
            //   8bbb97114000         | mov                 edi, dword ptr [ebx + 0x401197]

        $sequence_9 = { 66894308 6a10 ffb5a8050000 ffb5b8050000 }
            // n = 4, score = 100
            //   66894308             | mov                 word ptr [ebx + 8], ax
            //   6a10                 | push                0x10
            //   ffb5a8050000         | push                dword ptr [ebp + 0x5a8]
            //   ffb5b8050000         | push                dword ptr [ebp + 0x5b8]

        $sequence_10 = { c3 e8???????? 894500 0500200000 8985a0050000 0500200000 }
            // n = 6, score = 100
            //   c3                   | ret                 
            //   e8????????           |                     
            //   894500               | mov                 dword ptr [ebp], eax
            //   0500200000           | add                 eax, 0x2000
            //   8985a0050000         | mov                 dword ptr [ebp + 0x5a0], eax
            //   0500200000           | add                 eax, 0x2000

        $sequence_11 = { 3b8558080000 7308 83c004 83c304 ebe6 8b5d00 8b4308 }
            // n = 7, score = 100
            //   3b8558080000         | cmp                 eax, dword ptr [ebp + 0x858]
            //   7308                 | jae                 0xa
            //   83c004               | add                 eax, 4
            //   83c304               | add                 ebx, 4
            //   ebe6                 | jmp                 0xffffffe8
            //   8b5d00               | mov                 ebx, dword ptr [ebp]
            //   8b4308               | mov                 eax, dword ptr [ebx + 8]

        $sequence_12 = { 90 31c9 90 3108 90 }
            // n = 5, score = 100
            //   90                   | nop                 
            //   31c9                 | xor                 ecx, ecx
            //   90                   | nop                 
            //   3108                 | xor                 dword ptr [eax], ecx
            //   90                   | nop                 

        $sequence_13 = { 0050ff 15???????? c705????????00010000 68???????? 68???????? }
            // n = 5, score = 100
            //   0050ff               | add                 byte ptr [eax - 1], dl
            //   15????????           |                     
            //   c705????????00010000     |     
            //   68????????           |                     
            //   68????????           |                     

        $sequence_14 = { 90 8b1d???????? 90 8998f8070000 90 8b1d???????? }
            // n = 6, score = 100
            //   90                   | nop                 
            //   8b1d????????         |                     
            //   90                   | nop                 
            //   8998f8070000         | mov                 dword ptr [eax + 0x7f8], ebx
            //   90                   | nop                 
            //   8b1d????????         |                     

        $sequence_15 = { 7368 656c 6c 3332 2e646c }
            // n = 5, score = 100
            //   7368                 | jae                 0x6a
            //   656c                 | insb                byte ptr es:[edi], dx
            //   6c                   | insb                byte ptr es:[edi], dx
            //   3332                 | xor                 esi, dword ptr [edx]
            //   2e646c               | insb                byte ptr es:[edi], dx

    condition:
        7 of them and filesize < 40960
}