rule win_felismus_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.felismus."
        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.felismus"
        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 = { f3ab 8bca 83e103 f3aa 8b442410 33ff a9f0ffffff }
            // n = 7, score = 100
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   8bca                 | mov                 ecx, edx
            //   83e103               | and                 ecx, 3
            //   f3aa                 | rep stosb           byte ptr es:[edi], al
            //   8b442410             | mov                 eax, dword ptr [esp + 0x10]
            //   33ff                 | xor                 edi, edi
            //   a9f0ffffff           | test                eax, 0xfffffff0

        $sequence_1 = { 55 e8???????? 8bfd 83c9ff 33c0 83c408 }
            // n = 6, score = 100
            //   55                   | push                ebp
            //   e8????????           |                     
            //   8bfd                 | mov                 edi, ebp
            //   83c9ff               | or                  ecx, 0xffffffff
            //   33c0                 | xor                 eax, eax
            //   83c408               | add                 esp, 8

        $sequence_2 = { ff15???????? 85c0 6800040000 7464 e8???????? 8b5514 83c404 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   6800040000           | push                0x400
            //   7464                 | je                  0x66
            //   e8????????           |                     
            //   8b5514               | mov                 edx, dword ptr [ebp + 0x14]
            //   83c404               | add                 esp, 4

        $sequence_3 = { ff15???????? 8b4c2470 51 55 56 8d4c241c e8???????? }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   8b4c2470             | mov                 ecx, dword ptr [esp + 0x70]
            //   51                   | push                ecx
            //   55                   | push                ebp
            //   56                   | push                esi
            //   8d4c241c             | lea                 ecx, [esp + 0x1c]
            //   e8????????           |                     

        $sequence_4 = { 56 ffd7 8d54241c 6a00 52 6a01 68???????? }
            // n = 7, score = 100
            //   56                   | push                esi
            //   ffd7                 | call                edi
            //   8d54241c             | lea                 edx, [esp + 0x1c]
            //   6a00                 | push                0
            //   52                   | push                edx
            //   6a01                 | push                1
            //   68????????           |                     

        $sequence_5 = { 57 ffd3 55 ffd3 8b542430 52 ffd3 }
            // n = 7, score = 100
            //   57                   | push                edi
            //   ffd3                 | call                ebx
            //   55                   | push                ebp
            //   ffd3                 | call                ebx
            //   8b542430             | mov                 edx, dword ptr [esp + 0x30]
            //   52                   | push                edx
            //   ffd3                 | call                ebx

        $sequence_6 = { 50 ffd7 6a04 6800100000 6814030000 6a00 56 }
            // n = 7, score = 100
            //   50                   | push                eax
            //   ffd7                 | call                edi
            //   6a04                 | push                4
            //   6800100000           | push                0x1000
            //   6814030000           | push                0x314
            //   6a00                 | push                0
            //   56                   | push                esi

        $sequence_7 = { 50 68???????? eb4b 8d4c2458 51 ffd7 }
            // n = 6, score = 100
            //   50                   | push                eax
            //   68????????           |                     
            //   eb4b                 | jmp                 0x4d
            //   8d4c2458             | lea                 ecx, [esp + 0x58]
            //   51                   | push                ecx
            //   ffd7                 | call                edi

        $sequence_8 = { 53 55 56 57 6800040000 e8???????? 6800040000 }
            // n = 7, score = 100
            //   53                   | push                ebx
            //   55                   | push                ebp
            //   56                   | push                esi
            //   57                   | push                edi
            //   6800040000           | push                0x400
            //   e8????????           |                     
            //   6800040000           | push                0x400

        $sequence_9 = { c6432a23 c6432b20 f2ae f7d1 }
            // n = 4, score = 100
            //   c6432a23             | mov                 byte ptr [ebx + 0x2a], 0x23
            //   c6432b20             | mov                 byte ptr [ebx + 0x2b], 0x20
            //   f2ae                 | repne scasb         al, byte ptr es:[edi]
            //   f7d1                 | not                 ecx

    condition:
        7 of them and filesize < 204800
}