rule win_geckostealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.geckostealer."
        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.geckostealer"
        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 = { e8???????? e9???????? 48c1ef20 897d08 488b0e 488b4608 488d15cc6b4200 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   e9????????           |                     
            //   48c1ef20             | dec                 eax
            //   897d08               | sub                 esp, 0x38
            //   488b0e               | cmp                 dword ptr [ecx], 1
            //   488b4608             | je                  0x660
            //   488d15cc6b4200       | mov                 eax, dword ptr [ecx + 4]

        $sequence_1 = { c3 83c804 bd01000000 894630 4885d2 753a 480fbf4636 }
            // n = 7, score = 100
            //   c3                   | dec                 esp
            //   83c804               | add                 ebx, eax
            //   bd01000000           | and                 ecx, 7
            //   894630               | dec                 eax
            //   4885d2               | imul                ecx, ecx, 0x18
            //   753a                 | dec                 eax
            //   480fbf4636           | mov                 edi, dword ptr [edx + ecx + 8]

        $sequence_2 = { 897c2428 488b5108 488b09 4c89642420 e8???????? 8bd8 83fb01 }
            // n = 7, score = 100
            //   897c2428             | mov                 esi, 0x25
            //   488b5108             | xor                 ebx, ebx
            //   488b09               | dec                 eax
            //   4c89642420           | lea                 edi, [esp + 0x50]
            //   e8????????           |                     
            //   8bd8                 | mov                 dword ptr [esp + 0x28], ecx
            //   83fb01               | mov                 ecx, dword ptr [edi + 0x24]

        $sequence_3 = { e9???????? 4c8d249d01000000 4901ec e9???????? 4c8d249d02000000 4901ec e9???????? }
            // n = 7, score = 100
            //   e9????????           |                     
            //   4c8d249d01000000     | dec                 esp
            //   4901ec               | mov                 edx, ebp
            //   e9????????           |                     
            //   4c8d249d02000000     | inc                 ebp
            //   4901ec               | mov                 eax, edi
            //   e9????????           |                     

        $sequence_4 = { e9???????? 41bc01000000 eb06 41bc02000000 4901f4 488b6c2410 e9???????? }
            // n = 7, score = 100
            //   e9????????           |                     
            //   41bc01000000         | dec                 eax
            //   eb06                 | mov                 edi, dword ptr [ecx + 8]
            //   41bc02000000         | inc                 ecx
            //   4901f4               | push                esi
            //   488b6c2410           | push                esi
            //   e9????????           |                     

        $sequence_5 = { ebe6 4d85e4 488b7c2440 745d 488d05a4e23f00 4889442420 488d4c2468 }
            // n = 7, score = 100
            //   ebe6                 | mov                 byte ptr [eax + 8], dl
            //   4d85e4               | dec                 eax
            //   488b7c2440           | lea                 eax, [0x407f1d]
            //   745d                 | dec                 eax
            //   488d05a4e23f00       | mov                 dword ptr [esp + 0x20], eax
            //   4889442420           | dec                 eax
            //   488d4c2468           | lea                 ecx, [0x40ef81]

        $sequence_6 = { e8???????? cc 56 57 4881ec000a0000 4889ca 31c0 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   cc                   | add                 esp, 0x20
            //   56                   | pop                 esi
            //   57                   | ret                 
            //   4881ec000a0000       | dec                 ebp
            //   4889ca               | add                 eax, eax
            //   31c0                 | mov                 byte ptr [esi + 0x20], 1

        $sequence_7 = { eb55 c644242001 4889d9 4889fa 4989f0 4c8b4c2430 e8???????? }
            // n = 7, score = 100
            //   eb55                 | dec                 eax
            //   c644242001           | mov                 ecx, dword ptr [edi + 0x38]
            //   4889d9               | dec                 eax
            //   4889fa               | mov                 eax, ecx
            //   4989f0               | dec                 eax
            //   4c8b4c2430           | add                 eax, eax
            //   e8????????           |                     

        $sequence_8 = { eb23 4c8d05362d4600 eb35 4c8d05152d4600 eb1d 4801dd 4839ee }
            // n = 7, score = 100
            //   eb23                 | dec                 eax
            //   4c8d05362d4600       | mov                 ecx, dword ptr [edi + 0x20]
            //   eb35                 | dec                 eax
            //   4c8d05152d4600       | mov                 ecx, dword ptr [ecx + esi + 8]
            //   eb1d                 | cmp                 al, byte ptr [esp + 0x30]
            //   4801dd               | jne                 0xd03
            //   4839ee               | dec                 eax

        $sequence_9 = { eb46 243f 8bcf c1e90c 0480 81ff00000100 7314 }
            // n = 7, score = 100
            //   eb46                 | lea                 edi, [esp + 0xe0]
            //   243f                 | dec                 esp
            //   8bcf                 | mov                 ecx, edi
            //   c1e90c               | dec                 ecx
            //   0480                 | mov                 ecx, dword ptr [edi]
            //   81ff00000100         | dec                 ecx
            //   7314                 | mov                 edx, dword ptr [edi + 0x10]

    condition:
        7 of them and filesize < 12747776
}