rule win_sepsys_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.sepsys."
        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.sepsys"
        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 = { e8???????? 4889442430 488b4c2438 488b542430 e8???????? 2401 88442457 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   4889442430           | jne                 0x1515
            //   488b4c2438           | mov                 eax, 8
            //   488b542430           | dec                 eax
            //   e8????????           |                     
            //   2401                 | imul                eax, eax, 1
            //   88442457             | dec                 eax

        $sequence_1 = { c6452700 e9???????? f6452701 74ed c6452700 ebe7 f6452601 }
            // n = 7, score = 400
            //   c6452700             | dec                 eax
            //   e9????????           |                     
            //   f6452701             | lea                 ecx, [ebx + 0x2df0]
            //   74ed                 | dec                 eax
            //   c6452700             | lea                 edx, [ebx + 0x2e00]
            //   ebe7                 | vmovdqa             xmmword ptr [ebx + 0x2ee0], xmm5
            //   f6452601             | vmovdqa             xmm4, xmmword ptr [ebx + 0x2ed0]

        $sequence_2 = { eb00 488b4d00 488b5508 e8???????? 488945f8 eb00 488b45f8 }
            // n = 7, score = 400
            //   eb00                 | je                  0xfbb
            //   488b4d00             | mov                 eax, 0x41
            //   488b5508             | dec                 eax
            //   e8????????           |                     
            //   488945f8             | mov                 eax, dword ptr [esp + 0x28]
            //   eb00                 | dec                 eax
            //   488b45f8             | cmp                 dword ptr [eax + 0x6d0], 0

        $sequence_3 = { 488908 33c0 e9???????? 83bc24f800000005 7549 488b4c2458 e8???????? }
            // n = 7, score = 400
            //   488908               | lea                 edx, [0xd0318]
            //   33c0                 | dec                 eax
            //   e9????????           |                     
            //   83bc24f800000005     | lea                 ecx, [ebp - 0x28]
            //   7549                 | jmp                 0x152c
            //   488b4c2458           | dec                 esp
            //   e8????????           |                     

        $sequence_4 = { c685f600000000 488b45e0 480508000000 4889c1 e8???????? ebcf f685f500000001 }
            // n = 7, score = 400
            //   c685f600000000       | mov                 cl, byte ptr [eax]
            //   488b45e0             | mov                 byte ptr [esp + 0x77], cl
            //   480508000000         | cmp                 byte ptr [esp + 0x77], 0xc0
            //   4889c1               | setge               cl
            //   e8????????           |                     
            //   ebcf                 | mov                 byte ptr [esp + 0x66], 1
            //   f685f500000001       | inc                 esp

        $sequence_5 = { e8???????? 4889942418010000 4889842410010000 488b842410010000 4885c0 0f95c1 0fb6d1 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   4889942418010000     | mov                 eax, dword ptr [esp]
            //   4889842410010000     | dec                 eax
            //   488b842410010000     | mov                 ecx, dword ptr [esp + 8]
            //   4885c0               | dec                 eax
            //   0f95c1               | mov                 dword ptr [esp + 0x20], eax
            //   0fb6d1               | int3                

        $sequence_6 = { c744242400000000 eb0a 8b442424 ffc0 89442424 8b442424 4883f845 }
            // n = 7, score = 400
            //   c744242400000000     | lea                 ecx, [ebp - 0x18]
            //   eb0a                 | dec                 eax
            //   8b442424             | mov                 dword ptr [ebp - 0x30], eax
            //   ffc0                 | jmp                 0x1423
            //   89442424             | dec                 eax
            //   8b442424             | mov                 eax, dword ptr [ebp - 0x30]
            //   4883f845             | mov                 byte ptr [ebp + 0x4f], 0

        $sequence_7 = { e8???????? 84c0 7519 4889f1 4889da 4883c448 5b }
            // n = 7, score = 400
            //   e8????????           |                     
            //   84c0                 | dec                 eax
            //   7519                 | lea                 eax, [0x111049]
            //   4889f1               | dec                 eax
            //   4889da               | lea                 ecx, [0x11104a]
            //   4883c448             | dec                 eax
            //   5b                   | mov                 edx, dword ptr [esp + 0x78]

        $sequence_8 = { e8???????? 0f0b cc 55 56 4881ec88000000 488dac2480000000 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   0f0b                 | mov                 dword ptr [ebp + 0x110], 1
            //   cc                   | dec                 eax
            //   55                   | mov                 dword ptr [ebp + 0x28], eax
            //   56                   | mov                 byte ptr [ebp + 0xfa], 0
            //   4881ec88000000       | mov                 byte ptr [ebp + 0xfc], 1
            //   488dac2480000000     | dec                 eax

        $sequence_9 = { e8???????? eb0d 488b4500 4881c440050000 5d c3 488d95f0010000 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   eb0d                 | mov                 dword ptr [esp + 0xc68], eax
            //   488b4500             | dec                 eax
            //   4881c440050000       | mov                 eax, dword ptr [esp + 0xd0]
            //   5d                   | dec                 eax
            //   c3                   | mov                 dword ptr [esp + 0xc70], eax
            //   488d95f0010000       | mov                 ecx, dword ptr [esp + 0xc48]

    condition:
        7 of them and filesize < 4538368
}