rule win_bookcodesrat_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.bookcodesrat."
        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.bookcodesrat"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { 488bd8 e9???????? 498b5520 488b4cf508 488bc1 4803c9 4c8b44ca08 }
            // n = 7, score = 100
            //   488bd8               | dec                 eax
            //   e9????????           |                     
            //   498b5520             | inc                 edx
            //   488b4cf508           | xor                 al, cl
            //   488bc1               | inc                 ecx
            //   4803c9               | xor                 al, 0x33
            //   4c8b44ca08           | mov                 byte ptr [esp + edx + 0x37], al

        $sequence_1 = { 4883bb0037000000 0f8474050000 4885c0 0f846b050000 }
            // n = 4, score = 100
            //   4883bb0037000000     | movzx               ebx, byte ptr [esp + 0x6b]
            //   0f8474050000         | inc                 esp
            //   4885c0               | movzx               ecx, byte ptr [esp + 0x6d]
            //   0f846b050000         | inc                 esp

        $sequence_2 = { 5f 5e 5d c3 0fb6442460 }
            // n = 5, score = 100
            //   5f                   | inc                 esp
            //   5e                   | lea                 eax, [edx - 5]
            //   5d                   | dec                 eax
            //   c3                   | mov                 ecx, edi
            //   0fb6442460           | dec                 esp

        $sequence_3 = { 488bd9 4c8d44243c 33c9 c744243801000000 c744244402000000 ff15???????? 85c0 }
            // n = 7, score = 100
            //   488bd9               | inc                 ecx
            //   4c8d44243c           | movzx               eax, word ptr [esp]
            //   33c9                 | dec                 eax
            //   c744243801000000     | cmp                 dword ptr [ebp + esi*8 + 8], eax
            //   c744244402000000     | jne                 0x1427
            //   ff15????????         |                     
            //   85c0                 | dec                 ecx

        $sequence_4 = { 488d0d0d8d0200 e8???????? cc 488b4b18 483bcf 731c 488bd7 }
            // n = 7, score = 100
            //   488d0d0d8d0200       | dec                 esp
            //   e8????????           |                     
            //   cc                   | lea                 ebp, [0x15905]
            //   488b4b18             | neg                 esi
            //   483bcf               | dec                 ecx
            //   731c                 | cmp                 eax, 3
            //   488bd7               | setne               al

        $sequence_5 = { 498bd7 89742420 e8???????? 448be0 85c0 0f8559020000 }
            // n = 6, score = 100
            //   498bd7               | mov                 dword ptr [ebp + 0x591], eax
            //   89742420             | mov                 dword ptr [ebp + 0x244], 0x51474442
            //   e8????????           |                     
            //   448be0               | mov                 dword ptr [ebp + 0x248], 0x4a694e55
            //   85c0                 | mov                 dword ptr [ebp + 0x24c], 0x4f585d50
            //   0f8559020000         | mov                 byte ptr [ebp + 0x250], 0x50

        $sequence_6 = { e8???????? 85c0 786b 4c8bc5 488bd7 488bcb e8???????? }
            // n = 7, score = 100
            //   e8????????           |                     
            //   85c0                 | jl                  0x17bc
            //   786b                 | dec                 eax
            //   4c8bc5               | arpl                dx, ax
            //   488bd7               | inc                 edx
            //   488bcb               | xor                 al, 0x33
            //   e8????????           |                     

        $sequence_7 = { 498bcf e8???????? 48837f1000 7662 85f6 7e5e 48837b1000 }
            // n = 7, score = 100
            //   498bcf               | lea                 ecx, [ebp - 0x40]
            //   e8????????           |                     
            //   48837f1000           | xor                 eax, eax
            //   7662                 | dec                 eax
            //   85f6                 | or                  ecx, 0xffffffff
            //   7e5e                 | dec                 ebp
            //   48837b1000           | mov                 eax, esi

        $sequence_8 = { 48ffc3 4c3b6de8 0f820cffffff eb1f 4b8b84f8c0cb0300 f644300840 }
            // n = 6, score = 100
            //   48ffc3               | ret                 
            //   4c3b6de8             | dec                 eax
            //   0f820cffffff         | mov                 ecx, dword ptr [ebx + 0x418]
            //   eb1f                 | dec                 esp
            //   4b8b84f8c0cb0300     | mov                 dword ptr [esp + 0x20], esp
            //   f644300840           | call                dword ptr [ebx + 0x3670]

        $sequence_9 = { 4863c2 4c8bc1 8bd1 884c05b8 0f1f840000000000 420fb6840520010000 49ffc0 }
            // n = 7, score = 100
            //   4863c2               | dec                 esp
            //   4c8bc1               | mov                 ecx, esi
            //   8bd1                 | dec                 eax
            //   884c05b8             | mov                 ecx, esi
            //   0f1f840000000000     | dec                 esp
            //   420fb6840520010000     | mov    ebx, eax
            //   49ffc0               | dec                 eax

    condition:
        7 of them and filesize < 544768
}