rule win_beast_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.beast."
        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.beast"
        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 = { 8b74243c 33c0 50 8d442418 50 ffb424bc040000 ff36 }
            // n = 7, score = 100
            //   8b74243c             | mov                 esi, dword ptr [esp + 0x3c]
            //   33c0                 | xor                 eax, eax
            //   50                   | push                eax
            //   8d442418             | lea                 eax, [esp + 0x18]
            //   50                   | push                eax
            //   ffb424bc040000       | push                dword ptr [esp + 0x4bc]
            //   ff36                 | push                dword ptr [esi]

        $sequence_1 = { 83fa17 72ea 885c242b c64424387b c644243908 c644243a7c c644243b08 }
            // n = 7, score = 100
            //   83fa17               | cmp                 edx, 0x17
            //   72ea                 | jb                  0xffffffec
            //   885c242b             | mov                 byte ptr [esp + 0x2b], bl
            //   c64424387b           | mov                 byte ptr [esp + 0x38], 0x7b
            //   c644243908           | mov                 byte ptr [esp + 0x39], 8
            //   c644243a7c           | mov                 byte ptr [esp + 0x3a], 0x7c
            //   c644243b08           | mov                 byte ptr [esp + 0x3b], 8

        $sequence_2 = { 8b4e04 ba???????? e8???????? 59 8bc3 5f 5e }
            // n = 7, score = 100
            //   8b4e04               | mov                 ecx, dword ptr [esi + 4]
            //   ba????????           |                     
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   8bc3                 | mov                 eax, ebx
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_3 = { 8b442424 0423 8844244b 8b442424 0424 346f 8844244c }
            // n = 7, score = 100
            //   8b442424             | mov                 eax, dword ptr [esp + 0x24]
            //   0423                 | add                 al, 0x23
            //   8844244b             | mov                 byte ptr [esp + 0x4b], al
            //   8b442424             | mov                 eax, dword ptr [esp + 0x24]
            //   0424                 | add                 al, 0x24
            //   346f                 | xor                 al, 0x6f
            //   8844244c             | mov                 byte ptr [esp + 0x4c], al

        $sequence_4 = { 0f84c8000000 48 83e801 0f8486010000 48 83e801 0f840d010000 }
            // n = 7, score = 100
            //   0f84c8000000         | je                  0xce
            //   48                   | dec                 eax
            //   83e801               | sub                 eax, 1
            //   0f8486010000         | je                  0x18c
            //   48                   | dec                 eax
            //   83e801               | sub                 eax, 1
            //   0f840d010000         | je                  0x113

        $sequence_5 = { 33b1373e5000 8b4c2420 c1e910 0fb6c9 c1e104 8b542444 33b9323e5000 }
            // n = 7, score = 100
            //   33b1373e5000         | xor                 esi, dword ptr [ecx + 0x503e37]
            //   8b4c2420             | mov                 ecx, dword ptr [esp + 0x20]
            //   c1e910               | shr                 ecx, 0x10
            //   0fb6c9               | movzx               ecx, cl
            //   c1e104               | shl                 ecx, 4
            //   8b542444             | mov                 edx, dword ptr [esp + 0x44]
            //   33b9323e5000         | xor                 edi, dword ptr [ecx + 0x503e32]

        $sequence_6 = { 8884249c000000 8b44247c 041d 8884249d000000 8b44247c 041e 3465 }
            // n = 7, score = 100
            //   8884249c000000       | mov                 byte ptr [esp + 0x9c], al
            //   8b44247c             | mov                 eax, dword ptr [esp + 0x7c]
            //   041d                 | add                 al, 0x1d
            //   8884249d000000       | mov                 byte ptr [esp + 0x9d], al
            //   8b44247c             | mov                 eax, dword ptr [esp + 0x7c]
            //   041e                 | add                 al, 0x1e
            //   3465                 | xor                 al, 0x65

        $sequence_7 = { 85c0 0f8471030000 83f826 7603 6a26 58 0fb60c854e6c5000 }
            // n = 7, score = 100
            //   85c0                 | test                eax, eax
            //   0f8471030000         | je                  0x377
            //   83f826               | cmp                 eax, 0x26
            //   7603                 | jbe                 5
            //   6a26                 | push                0x26
            //   58                   | pop                 eax
            //   0fb60c854e6c5000     | movzx               ecx, byte ptr [eax*4 + 0x506c4e]

        $sequence_8 = { 56 8b35???????? 50 ffd6 8d0c4502000000 e8???????? 57 }
            // n = 7, score = 100
            //   56                   | push                esi
            //   8b35????????         |                     
            //   50                   | push                eax
            //   ffd6                 | call                esi
            //   8d0c4502000000       | lea                 ecx, [eax*2 + 2]
            //   e8????????           |                     
            //   57                   | push                edi

        $sequence_9 = { 330c8550a84f00 894c2424 8b4c241c 8b742424 0fb6c1 c1e908 0fb6c9 }
            // n = 7, score = 100
            //   330c8550a84f00       | xor                 ecx, dword ptr [eax*4 + 0x4fa850]
            //   894c2424             | mov                 dword ptr [esp + 0x24], ecx
            //   8b4c241c             | mov                 ecx, dword ptr [esp + 0x1c]
            //   8b742424             | mov                 esi, dword ptr [esp + 0x24]
            //   0fb6c1               | movzx               eax, cl
            //   c1e908               | shr                 ecx, 8
            //   0fb6c9               | movzx               ecx, cl

    condition:
        7 of them and filesize < 2411520
}