rule win_nachocheese_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.nachocheese."
        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.nachocheese"
        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 = { 83f817 7532 8b7710 8b5f18 85f6 }
            // n = 5, score = 300
            //   83f817               | cmp                 eax, 0x17
            //   7532                 | jne                 0x34
            //   8b7710               | mov                 esi, dword ptr [edi + 0x10]
            //   8b5f18               | mov                 ebx, dword ptr [edi + 0x18]
            //   85f6                 | test                esi, esi

        $sequence_1 = { 3d2bc00000 7d1b 3d9c000000 7c07 }
            // n = 4, score = 300
            //   3d2bc00000           | cmp                 eax, 0xc02b
            //   7d1b                 | jge                 0x1d
            //   3d9c000000           | cmp                 eax, 0x9c
            //   7c07                 | jl                  9

        $sequence_2 = { 8a540305 32d1 88143e 8a4805 02ca 880c3e }
            // n = 6, score = 300
            //   8a540305             | mov                 dl, byte ptr [ebx + eax + 5]
            //   32d1                 | xor                 dl, cl
            //   88143e               | mov                 byte ptr [esi + edi], dl
            //   8a4805               | mov                 cl, byte ptr [eax + 5]
            //   02ca                 | add                 cl, dl
            //   880c3e               | mov                 byte ptr [esi + edi], cl

        $sequence_3 = { 33c8 894710 8b4708 33c1 }
            // n = 4, score = 300
            //   33c8                 | xor                 ecx, eax
            //   894710               | mov                 dword ptr [edi + 0x10], eax
            //   8b4708               | mov                 eax, dword ptr [edi + 8]
            //   33c1                 | xor                 eax, ecx

        $sequence_4 = { ff15???????? 85c0 7473 8b55f4 }
            // n = 4, score = 300
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7473                 | je                  0x75
            //   8b55f4               | mov                 edx, dword ptr [ebp - 0xc]

        $sequence_5 = { 3d9f000000 7e0d 33c0 c3 05d13fffff 83f801 77f3 }
            // n = 7, score = 300
            //   3d9f000000           | cmp                 eax, 0x9f
            //   7e0d                 | jle                 0xf
            //   33c0                 | xor                 eax, eax
            //   c3                   | ret                 
            //   05d13fffff           | add                 eax, 0xffff3fd1
            //   83f801               | cmp                 eax, 1
            //   77f3                 | ja                  0xfffffff5

        $sequence_6 = { 33f6 397508 0f8ec9000000 b8???????? 48 }
            // n = 5, score = 300
            //   33f6                 | xor                 esi, esi
            //   397508               | cmp                 dword ptr [ebp + 8], esi
            //   0f8ec9000000         | jle                 0xcf
            //   b8????????           |                     
            //   48                   | dec                 eax

        $sequence_7 = { 7305 83c302 eb29 81fb00010000 }
            // n = 4, score = 300
            //   7305                 | jae                 7
            //   83c302               | add                 ebx, 2
            //   eb29                 | jmp                 0x2b
            //   81fb00010000         | cmp                 ebx, 0x100

        $sequence_8 = { 3d2cc00000 7f18 3d2bc00000 7d1b }
            // n = 4, score = 300
            //   3d2cc00000           | cmp                 eax, 0xc02c
            //   7f18                 | jg                  0x1a
            //   3d2bc00000           | cmp                 eax, 0xc02b
            //   7d1b                 | jge                 0x1d

        $sequence_9 = { 7305 83c303 eb1c 81fb00000100 7305 83c304 eb0f }
            // n = 7, score = 300
            //   7305                 | jae                 7
            //   83c303               | add                 ebx, 3
            //   eb1c                 | jmp                 0x1e
            //   81fb00000100         | cmp                 ebx, 0x10000
            //   7305                 | jae                 7
            //   83c304               | add                 ebx, 4
            //   eb0f                 | jmp                 0x11

        $sequence_10 = { c3 8d85ecfaffff 68???????? 50 }
            // n = 4, score = 300
            //   c3                   | ret                 
            //   8d85ecfaffff         | lea                 eax, [ebp - 0x514]
            //   68????????           |                     
            //   50                   | push                eax

        $sequence_11 = { 55 8bec 8b4508 50 81c10e010000 6804010000 }
            // n = 6, score = 300
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   50                   | push                eax
            //   81c10e010000         | add                 ecx, 0x10e
            //   6804010000           | push                0x104

        $sequence_12 = { 8b4508 8b4dfc 6a00 8d55f8 }
            // n = 4, score = 300
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   6a00                 | push                0
            //   8d55f8               | lea                 edx, [ebp - 8]

        $sequence_13 = { 2bfa 8d47fd 3901 8901 }
            // n = 4, score = 300
            //   2bfa                 | sub                 edi, edx
            //   8d47fd               | lea                 eax, [edi - 3]
            //   3901                 | cmp                 dword ptr [ecx], eax
            //   8901                 | mov                 dword ptr [ecx], eax

        $sequence_14 = { 68???????? eb38 8dbc24a0010000 8bce e8???????? 8bd7 52 }
            // n = 7, score = 300
            //   68????????           |                     
            //   eb38                 | jmp                 0x3a
            //   8dbc24a0010000       | lea                 edi, [esp + 0x1a0]
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   8bd7                 | mov                 edx, edi
            //   52                   | push                edx

        $sequence_15 = { 3d9c000000 7c07 3d9f000000 7e0d }
            // n = 4, score = 300
            //   3d9c000000           | cmp                 eax, 0x9c
            //   7c07                 | jl                  9
            //   3d9f000000           | cmp                 eax, 0x9f
            //   7e0d                 | jle                 0xf

    condition:
        7 of them and filesize < 1064960
}