rule win_bitsran_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.bitsran."
        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.bitsran"
        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 = { 030495a01f4200 eb05 b8???????? f6400420 7414 6a02 53 }
            // n = 7, score = 100
            //   030495a01f4200       | add                 eax, dword ptr [edx*4 + 0x421fa0]
            //   eb05                 | jmp                 7
            //   b8????????           |                     
            //   f6400420             | test                byte ptr [eax + 4], 0x20
            //   7414                 | je                  0x16
            //   6a02                 | push                2
            //   53                   | push                ebx

        $sequence_1 = { 8b4508 33c9 3b04cda8034200 7413 41 83f92d }
            // n = 6, score = 100
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   33c9                 | xor                 ecx, ecx
            //   3b04cda8034200       | cmp                 eax, dword ptr [ecx*8 + 0x4203a8]
            //   7413                 | je                  0x15
            //   41                   | inc                 ecx
            //   83f92d               | cmp                 ecx, 0x2d

        $sequence_2 = { 8bc7 c1f805 c1e606 033485a01f4200 8b45f8 }
            // n = 5, score = 100
            //   8bc7                 | mov                 eax, edi
            //   c1f805               | sar                 eax, 5
            //   c1e606               | shl                 esi, 6
            //   033485a01f4200       | add                 esi, dword ptr [eax*4 + 0x421fa0]
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]

        $sequence_3 = { 8bd1 c1fa05 c1e006 030495a01f4200 eb05 }
            // n = 5, score = 100
            //   8bd1                 | mov                 edx, ecx
            //   c1fa05               | sar                 edx, 5
            //   c1e006               | shl                 eax, 6
            //   030495a01f4200       | add                 eax, dword ptr [edx*4 + 0x421fa0]
            //   eb05                 | jmp                 7

        $sequence_4 = { 83ec54 56 8b7508 85f6 7508 83c8ff }
            // n = 6, score = 100
            //   83ec54               | sub                 esp, 0x54
            //   56                   | push                esi
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]
            //   85f6                 | test                esi, esi
            //   7508                 | jne                 0xa
            //   83c8ff               | or                  eax, 0xffffffff

        $sequence_5 = { 57 8d45ec 50 8d8decfbffff }
            // n = 4, score = 100
            //   57                   | push                edi
            //   8d45ec               | lea                 eax, [ebp - 0x14]
            //   50                   | push                eax
            //   8d8decfbffff         | lea                 ecx, [ebp - 0x414]

        $sequence_6 = { 75e6 c6460401 830eff 2b34bda01f4200 }
            // n = 4, score = 100
            //   75e6                 | jne                 0xffffffe8
            //   c6460401             | mov                 byte ptr [esi + 4], 1
            //   830eff               | or                  dword ptr [esi], 0xffffffff
            //   2b34bda01f4200       | sub                 esi, dword ptr [edi*4 + 0x421fa0]

        $sequence_7 = { ff15???????? 6803010000 8d85f1fcffff 6a00 50 c685f0fcffff00 }
            // n = 6, score = 100
            //   ff15????????         |                     
            //   6803010000           | push                0x103
            //   8d85f1fcffff         | lea                 eax, [ebp - 0x30f]
            //   6a00                 | push                0
            //   50                   | push                eax
            //   c685f0fcffff00       | mov                 byte ptr [ebp - 0x310], 0

        $sequence_8 = { 8a85eefcffff 8a8deffcffff c7830c02000000000000 84c9 740a }
            // n = 5, score = 100
            //   8a85eefcffff         | mov                 al, byte ptr [ebp - 0x312]
            //   8a8deffcffff         | mov                 cl, byte ptr [ebp - 0x311]
            //   c7830c02000000000000     | mov    dword ptr [ebx + 0x20c], 0
            //   84c9                 | test                cl, cl
            //   740a                 | je                  0xc

        $sequence_9 = { 3bfa 7553 8bc7 2bc3 c1f802 3dfeffff3f 775c }
            // n = 7, score = 100
            //   3bfa                 | cmp                 edi, edx
            //   7553                 | jne                 0x55
            //   8bc7                 | mov                 eax, edi
            //   2bc3                 | sub                 eax, ebx
            //   c1f802               | sar                 eax, 2
            //   3dfeffff3f           | cmp                 eax, 0x3ffffffe
            //   775c                 | ja                  0x5e

    condition:
        7 of them and filesize < 344064
}