rule win_xtinyloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.xtinyloader."
        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.xtinyloader"
        malpedia_rule_date = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { c3 3bfb 7615 8b4d08 2bce 8bd7 8a1c01 }
            // n = 7, score = 100
            //   c3                   | ret                 
            //   3bfb                 | cmp                 edi, ebx
            //   7615                 | jbe                 0x17
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   2bce                 | sub                 ecx, esi
            //   8bd7                 | mov                 edx, edi
            //   8a1c01               | mov                 bl, byte ptr [ecx + eax]

        $sequence_1 = { ff15???????? 43 83fb05 72e7 56 ff15???????? 85c0 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   43                   | inc                 ebx
            //   83fb05               | cmp                 ebx, 5
            //   72e7                 | jb                  0xffffffe9
            //   56                   | push                esi
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax

        $sequence_2 = { 56 33f6 57 397508 0f84da000000 0fb605???????? 50 }
            // n = 7, score = 100
            //   56                   | push                esi
            //   33f6                 | xor                 esi, esi
            //   57                   | push                edi
            //   397508               | cmp                 dword ptr [ebp + 8], esi
            //   0f84da000000         | je                  0xe0
            //   0fb605????????       |                     
            //   50                   | push                eax

        $sequence_3 = { ff35???????? ff35???????? e8???????? 50 53 ff15???????? 83c414 }
            // n = 7, score = 100
            //   ff35????????         |                     
            //   ff35????????         |                     
            //   e8????????           |                     
            //   50                   | push                eax
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   83c414               | add                 esp, 0x14

        $sequence_4 = { 393d???????? 0f8459010000 393d???????? 0f844d010000 393d???????? }
            // n = 5, score = 100
            //   393d????????         |                     
            //   0f8459010000         | je                  0x15f
            //   393d????????         |                     
            //   0f844d010000         | je                  0x153
            //   393d????????         |                     

        $sequence_5 = { ff15???????? eb8e 53 56 ff15???????? 8b4c240c 0fb719 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   eb8e                 | jmp                 0xffffff90
            //   53                   | push                ebx
            //   56                   | push                esi
            //   ff15????????         |                     
            //   8b4c240c             | mov                 ecx, dword ptr [esp + 0xc]
            //   0fb719               | movzx               ebx, word ptr [ecx]

        $sequence_6 = { 83c40c 3bde 750a 57 ff15???????? }
            // n = 5, score = 100
            //   83c40c               | add                 esp, 0xc
            //   3bde                 | cmp                 ebx, esi
            //   750a                 | jne                 0xc
            //   57                   | push                edi
            //   ff15????????         |                     

        $sequence_7 = { a1???????? 85c0 746a 8d4dbc 51 ffd0 66837dbc09 }
            // n = 7, score = 100
            //   a1????????           |                     
            //   85c0                 | test                eax, eax
            //   746a                 | je                  0x6c
            //   8d4dbc               | lea                 ecx, [ebp - 0x44]
            //   51                   | push                ecx
            //   ffd0                 | call                eax
            //   66837dbc09           | cmp                 word ptr [ebp - 0x44], 9

        $sequence_8 = { 894508 ff15???????? 397508 75cd }
            // n = 4, score = 100
            //   894508               | mov                 dword ptr [ebp + 8], eax
            //   ff15????????         |                     
            //   397508               | cmp                 dword ptr [ebp + 8], esi
            //   75cd                 | jne                 0xffffffcf

        $sequence_9 = { 59 6a5c 6689480a 59 }
            // n = 4, score = 100
            //   59                   | pop                 ecx
            //   6a5c                 | push                0x5c
            //   6689480a             | mov                 word ptr [eax + 0xa], cx
            //   59                   | pop                 ecx

    condition:
        7 of them and filesize < 50176
}