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
}