rule win_xtinyloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        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 = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { 51 ffd0 66837dbc09 754d c745e801000000 0fb605???????? 50 }
            // n = 7, score = 100
            //   51                   | push                ecx
            //   ffd0                 | call                eax
            //   66837dbc09           | cmp                 word ptr [ebp - 0x44], 9
            //   754d                 | jne                 0x4f
            //   c745e801000000       | mov                 dword ptr [ebp - 0x18], 1
            //   0fb605????????       |                     
            //   50                   | push                eax

        $sequence_1 = { 803b00 8bcb 7407 46 41 803900 }
            // n = 6, score = 100
            //   803b00               | cmp                 byte ptr [ebx], 0
            //   8bcb                 | mov                 ecx, ebx
            //   7407                 | je                  9
            //   46                   | inc                 esi
            //   41                   | inc                 ecx
            //   803900               | cmp                 byte ptr [ecx], 0

        $sequence_2 = { ff75f4 ff15???????? ff75ec ff15???????? 56 6a40 }
            // n = 6, score = 100
            //   ff75f4               | push                dword ptr [ebp - 0xc]
            //   ff15????????         |                     
            //   ff75ec               | push                dword ptr [ebp - 0x14]
            //   ff15????????         |                     
            //   56                   | push                esi
            //   6a40                 | push                0x40

        $sequence_3 = { 83f820 7e03 33db 43 57 }
            // n = 5, score = 100
            //   83f820               | cmp                 eax, 0x20
            //   7e03                 | jle                 5
            //   33db                 | xor                 ebx, ebx
            //   43                   | inc                 ebx
            //   57                   | push                edi

        $sequence_4 = { ff15???????? 8945f0 3bc6 7509 53 ff15???????? ebde }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   3bc6                 | cmp                 eax, esi
            //   7509                 | jne                 0xb
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   ebde                 | jmp                 0xffffffe0

        $sequence_5 = { 57 ff15???????? 395d10 740b ff7510 }
            // n = 5, score = 100
            //   57                   | push                edi
            //   ff15????????         |                     
            //   395d10               | cmp                 dword ptr [ebp + 0x10], ebx
            //   740b                 | je                  0xd
            //   ff7510               | push                dword ptr [ebp + 0x10]

        $sequence_6 = { 83c410 85c0 740d 8d859cd9ffff }
            // n = 4, score = 100
            //   83c410               | add                 esp, 0x10
            //   85c0                 | test                eax, eax
            //   740d                 | je                  0xf
            //   8d859cd9ffff         | lea                 eax, [ebp - 0x2664]

        $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 = { ff75ec eba6 57 ff15???????? 8945e4 85c0 7509 }
            // n = 7, score = 100
            //   ff75ec               | push                dword ptr [ebp - 0x14]
            //   eba6                 | jmp                 0xffffffa8
            //   57                   | push                edi
            //   ff15????????         |                     
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax
            //   85c0                 | test                eax, eax
            //   7509                 | jne                 0xb

        $sequence_9 = { 807e0163 7545 807e0231 753f 33c9 3c62 0f94c1 }
            // n = 7, score = 100
            //   807e0163             | cmp                 byte ptr [esi + 1], 0x63
            //   7545                 | jne                 0x47
            //   807e0231             | cmp                 byte ptr [esi + 2], 0x31
            //   753f                 | jne                 0x41
            //   33c9                 | xor                 ecx, ecx
            //   3c62                 | cmp                 al, 0x62
            //   0f94c1               | sete                cl

    condition:
        7 of them and filesize < 50176
}