rule win_croxloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.croxloader."
        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.croxloader"
        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 = { 4803ce 488bd7 e8???????? 4533db 498bd3 4c8d051f66ffff 4b8b8ce010970100 }
            // n = 7, score = 100
            //   4803ce               | lea                 ecx, [0x159d0]
            //   488bd7               | dec                 eax
            //   e8????????           |                     
            //   4533db               | ror                 edx, cl
            //   498bd3               | dec                 ecx
            //   4c8d051f66ffff       | xor                 edx, eax
            //   4b8b8ce010970100     | dec                 ebx

        $sequence_1 = { 488d442450 48897c2448 41b940000000 4889442420 48c7c1ffffffff }
            // n = 5, score = 100
            //   488d442450           | dec                 ebp
            //   48897c2448           | mov                 ecx, dword ptr [edi + eax*8 + 0x19710]
            //   41b940000000         | dec                 ecx
            //   4889442420           | mov                 esi, ebx
            //   48c7c1ffffffff       | jne                 0x207

        $sequence_2 = { 7542 8d58b0 498bce 448bc3 488d1520750000 e8???????? }
            // n = 6, score = 100
            //   7542                 | dec                 ebp
            //   8d58b0               | test                eax, eax
            //   498bce               | jle                 0x3b9
            //   448bc3               | dec                 eax
            //   488d1520750000       | sub                 edi, esi
            //   e8????????           |                     

        $sequence_3 = { e8???????? 4c8d05dd880100 badab3f10d b95595db6d }
            // n = 4, score = 100
            //   e8????????           |                     
            //   4c8d05dd880100       | mov                 eax, edx
            //   badab3f10d           | dec                 esp
            //   b95595db6d           | add                 ebx, ebx

        $sequence_4 = { 488d05be1c0100 483bc8 7405 e8???????? c70301000000 488bcb 488b4530 }
            // n = 7, score = 100
            //   488d05be1c0100       | dec                 eax
            //   483bc8               | mov                 eax, edx
            //   7405                 | dec                 eax
            //   e8????????           |                     
            //   c70301000000         | sar                 eax, 6
            //   488bcb               | jae                 0xfb
            //   488b4530             | dec                 eax

        $sequence_5 = { 4053 4883ec20 8bd9 4c8d0db1ad0000 b902000000 }
            // n = 5, score = 100
            //   4053                 | mov                 edx, ebx
            //   4883ec20             | dec                 ebp
            //   8bd9                 | mov                 ecx, dword ptr [edi + eax*8 + 0x19710]
            //   4c8d0db1ad0000       | dec                 ecx
            //   b902000000           | mov                 esi, ebx

        $sequence_6 = { 0f1f440000 4d8b5a60 bb05150000 450fb74a58 498bc3 440fb600 }
            // n = 6, score = 100
            //   0f1f440000           | mov                 ecx, 0x16
            //   4d8b5a60             | dec                 esp
            //   bb05150000           | lea                 eax, [0x7abb]
            //   450fb74a58           | dec                 eax
            //   498bc3               | mov                 ebx, ecx
            //   440fb600             | dec                 eax

        $sequence_7 = { b906000000 4c8d05277c0000 e8???????? 488bd3 8bcf }
            // n = 5, score = 100
            //   b906000000           | cmp                 edi, edx
            //   4c8d05277c0000       | dec                 eax
            //   e8????????           |                     
            //   488bd3               | mov                 dword ptr [eax], ecx
            //   8bcf                 | dec                 eax

        $sequence_8 = { 0f8ee0000000 4b8b84e710970100 4c8b45af 4c2bc7 420fb64cf03e }
            // n = 5, score = 100
            //   0f8ee0000000         | dec                 eax
            //   4b8b84e710970100     | mov                 edx, edi
            //   4c8b45af             | dec                 eax
            //   4c2bc7               | mov                 ecx, ebx
            //   420fb64cf03e         | dec                 esp

        $sequence_9 = { 0f8ee0000000 4b8b84e710970100 4c8b45af 4c2bc7 420fb64cf03e 460fbebc39c0880100 41ffc7 }
            // n = 7, score = 100
            //   0f8ee0000000         | lea                 ecx, [0xbc2b]
            //   4b8b84e710970100     | test                eax, eax
            //   4c8b45af             | jne                 0x3c3
            //   4c2bc7               | test                al, al
            //   420fb64cf03e         | dec                 eax
            //   460fbebc39c0880100     | lea    ecx, [0x17339]
            //   41ffc7               | dec                 eax

    condition:
        7 of them and filesize < 241664
}