rule win_yoddos_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.yoddos."
        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.yoddos"
        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 = { ff15???????? 50 ffd6 b863000000 90 b89dffffff 90 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   50                   | push                eax
            //   ffd6                 | call                esi
            //   b863000000           | mov                 eax, 0x63
            //   90                   | nop                 
            //   b89dffffff           | mov                 eax, 0xffffff9d
            //   90                   | nop                 

        $sequence_1 = { ffd7 50 ffd6 898538ffffff 899d50ffffff 899d3cffffff c68554ffffff4d }
            // n = 7, score = 100
            //   ffd7                 | call                edi
            //   50                   | push                eax
            //   ffd6                 | call                esi
            //   898538ffffff         | mov                 dword ptr [ebp - 0xc8], eax
            //   899d50ffffff         | mov                 dword ptr [ebp - 0xb0], ebx
            //   899d3cffffff         | mov                 dword ptr [ebp - 0xc4], ebx
            //   c68554ffffff4d       | mov                 byte ptr [ebp - 0xac], 0x4d

        $sequence_2 = { c78554ffffff00000001 e8???????? 6ada 8d8554ffffff 6a64 50 e8???????? }
            // n = 7, score = 100
            //   c78554ffffff00000001     | mov    dword ptr [ebp - 0xac], 0x1000000
            //   e8????????           |                     
            //   6ada                 | push                -0x26
            //   8d8554ffffff         | lea                 eax, [ebp - 0xac]
            //   6a64                 | push                0x64
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_3 = { 66ab 59 33c0 8dbda1feffff 889da0feffff f3ab }
            // n = 6, score = 100
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   59                   | pop                 ecx
            //   33c0                 | xor                 eax, eax
            //   8dbda1feffff         | lea                 edi, [ebp - 0x15f]
            //   889da0feffff         | mov                 byte ptr [ebp - 0x160], bl
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax

        $sequence_4 = { 8d85fcfdffff 53 50 ff35???????? e8???????? 59 40 }
            // n = 7, score = 100
            //   8d85fcfdffff         | lea                 eax, [ebp - 0x204]
            //   53                   | push                ebx
            //   50                   | push                eax
            //   ff35????????         |                     
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   40                   | inc                 eax

        $sequence_5 = { 8d45d4 6a10 50 56 ebf0 }
            // n = 5, score = 100
            //   8d45d4               | lea                 eax, [ebp - 0x2c]
            //   6a10                 | push                0x10
            //   50                   | push                eax
            //   56                   | push                esi
            //   ebf0                 | jmp                 0xfffffff2

        $sequence_6 = { 898550fcffff ffd6 8b8d54fcffff 53 0fb7c0 6683e100 }
            // n = 6, score = 100
            //   898550fcffff         | mov                 dword ptr [ebp - 0x3b0], eax
            //   ffd6                 | call                esi
            //   8b8d54fcffff         | mov                 ecx, dword ptr [ebp - 0x3ac]
            //   53                   | push                ebx
            //   0fb7c0               | movzx               eax, ax
            //   6683e100             | and                 cx, 0

        $sequence_7 = { 8bf1 c1f805 83e61f 8d3c8500764100 c1e603 8b07 03c6 }
            // n = 7, score = 100
            //   8bf1                 | mov                 esi, ecx
            //   c1f805               | sar                 eax, 5
            //   83e61f               | and                 esi, 0x1f
            //   8d3c8500764100       | lea                 edi, [eax*4 + 0x417600]
            //   c1e603               | shl                 esi, 3
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   03c6                 | add                 eax, esi

        $sequence_8 = { 83bdf4feffff04 7710 8d4618 68???????? 50 e8???????? 59 }
            // n = 7, score = 100
            //   83bdf4feffff04       | cmp                 dword ptr [ebp - 0x10c], 4
            //   7710                 | ja                  0x12
            //   8d4618               | lea                 eax, [esi + 0x18]
            //   68????????           |                     
            //   50                   | push                eax
            //   e8????????           |                     
            //   59                   | pop                 ecx

        $sequence_9 = { e9???????? 57 6a40 59 33c0 8dbdf9feffff 889df8feffff }
            // n = 7, score = 100
            //   e9????????           |                     
            //   57                   | push                edi
            //   6a40                 | push                0x40
            //   59                   | pop                 ecx
            //   33c0                 | xor                 eax, eax
            //   8dbdf9feffff         | lea                 edi, [ebp - 0x107]
            //   889df8feffff         | mov                 byte ptr [ebp - 0x108], bl

    condition:
        7 of them and filesize < 557056
}