rule win_chthonic_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.chthonic."
        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.chthonic"
        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 = { 5f c1ee1f e9???????? 8b041a 8bc8 83c204 }
            // n = 6, score = 600
            //   5f                   | pop                 edi
            //   c1ee1f               | shr                 esi, 0x1f
            //   e9????????           |                     
            //   8b041a               | mov                 eax, dword ptr [edx + ebx]
            //   8bc8                 | mov                 ecx, eax
            //   83c204               | add                 edx, 4

        $sequence_1 = { 53 ff7510 ff7508 e8???????? 85c0 7502 b301 }
            // n = 7, score = 600
            //   53                   | push                ebx
            //   ff7510               | push                dword ptr [ebp + 0x10]
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   7502                 | jne                 4
            //   b301                 | mov                 bl, 1

        $sequence_2 = { 3bc3 7cf4 33f6 33d2 8bc6 f77514 }
            // n = 6, score = 600
            //   3bc3                 | cmp                 eax, ebx
            //   7cf4                 | jl                  0xfffffff6
            //   33f6                 | xor                 esi, esi
            //   33d2                 | xor                 edx, edx
            //   8bc6                 | mov                 eax, esi
            //   f77514               | div                 dword ptr [ebp + 0x14]

        $sequence_3 = { 81e1ff00ff00 0bc1 89470c 5f }
            // n = 4, score = 600
            //   81e1ff00ff00         | and                 ecx, 0xff00ff
            //   0bc1                 | or                  eax, ecx
            //   89470c               | mov                 dword ptr [edi + 0xc], eax
            //   5f                   | pop                 edi

        $sequence_4 = { 894dfc 85ff 7459 4f 8bf0 }
            // n = 5, score = 600
            //   894dfc               | mov                 dword ptr [ebp - 4], ecx
            //   85ff                 | test                edi, edi
            //   7459                 | je                  0x5b
            //   4f                   | dec                 edi
            //   8bf0                 | mov                 esi, eax

        $sequence_5 = { ff45f4 ff4dfc 75ec 894df4 e9???????? 8b041a }
            // n = 6, score = 600
            //   ff45f4               | inc                 dword ptr [ebp - 0xc]
            //   ff4dfc               | dec                 dword ptr [ebp - 4]
            //   75ec                 | jne                 0xffffffee
            //   894df4               | mov                 dword ptr [ebp - 0xc], ecx
            //   e9????????           |                     
            //   8b041a               | mov                 eax, dword ptr [edx + ebx]

        $sequence_6 = { c1c108 81e1ff00ff00 0bc1 89470c }
            // n = 4, score = 600
            //   c1c108               | rol                 ecx, 8
            //   81e1ff00ff00         | and                 ecx, 0xff00ff
            //   0bc1                 | or                  eax, ecx
            //   89470c               | mov                 dword ptr [edi + 0xc], eax

        $sequence_7 = { eb00 85ff 0f84bd000000 4f 8bf0 }
            // n = 5, score = 600
            //   eb00                 | jmp                 2
            //   85ff                 | test                edi, edi
            //   0f84bd000000         | je                  0xc3
            //   4f                   | dec                 edi
            //   8bf0                 | mov                 esi, eax

        $sequence_8 = { 83fe02 0f850d010000 8b4df0 eb00 894df8 85ff 0f84e7000000 }
            // n = 7, score = 600
            //   83fe02               | cmp                 esi, 2
            //   0f850d010000         | jne                 0x113
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]
            //   eb00                 | jmp                 2
            //   894df8               | mov                 dword ptr [ebp - 8], ecx
            //   85ff                 | test                edi, edi
            //   0f84e7000000         | je                  0xed

        $sequence_9 = { ff751c ff7518 ff7514 53 ff7510 ff7508 e8???????? }
            // n = 7, score = 600
            //   ff751c               | push                dword ptr [ebp + 0x1c]
            //   ff7518               | push                dword ptr [ebp + 0x18]
            //   ff7514               | push                dword ptr [ebp + 0x14]
            //   53                   | push                ebx
            //   ff7510               | push                dword ptr [ebp + 0x10]
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     

    condition:
        7 of them and filesize < 425984
}