rule win_former_first_rat_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.former_first_rat."
        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.former_first_rat"
        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 = { 57 e8???????? 83c404 56 e8???????? 8b8504ffffff 83c404 }
            // n = 7, score = 200
            //   57                   | push                edi
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   56                   | push                esi
            //   e8????????           |                     
            //   8b8504ffffff         | mov                 eax, dword ptr [ebp - 0xfc]
            //   83c404               | add                 esp, 4

        $sequence_1 = { 8d8de0feffff 51 bb08000000 e8???????? 8b9df8feffff 57 e8???????? }
            // n = 7, score = 200
            //   8d8de0feffff         | lea                 ecx, [ebp - 0x120]
            //   51                   | push                ecx
            //   bb08000000           | mov                 ebx, 8
            //   e8????????           |                     
            //   8b9df8feffff         | mov                 ebx, dword ptr [ebp - 0x108]
            //   57                   | push                edi
            //   e8????????           |                     

        $sequence_2 = { 75f8 8d85b4feffff 68???????? b90d000000 be???????? 50 }
            // n = 6, score = 200
            //   75f8                 | jne                 0xfffffffa
            //   8d85b4feffff         | lea                 eax, [ebp - 0x14c]
            //   68????????           |                     
            //   b90d000000           | mov                 ecx, 0xd
            //   be????????           |                     
            //   50                   | push                eax

        $sequence_3 = { 740a c705????????05000000 6a59 ffd6 }
            // n = 4, score = 200
            //   740a                 | je                  0xc
            //   c705????????05000000     |     
            //   6a59                 | push                0x59
            //   ffd6                 | call                esi

        $sequence_4 = { 81c208020000 f3a5 3b44240c 75e4 }
            // n = 4, score = 200
            //   81c208020000         | add                 edx, 0x208
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   3b44240c             | cmp                 eax, dword ptr [esp + 0xc]
            //   75e4                 | jne                 0xffffffe6

        $sequence_5 = { 8d85f4efffff 6a00 50 e8???????? 8b85e4eeffff 83c40c }
            // n = 6, score = 200
            //   8d85f4efffff         | lea                 eax, [ebp - 0x100c]
            //   6a00                 | push                0
            //   50                   | push                eax
            //   e8????????           |                     
            //   8b85e4eeffff         | mov                 eax, dword ptr [ebp - 0x111c]
            //   83c40c               | add                 esp, 0xc

        $sequence_6 = { 2bf1 b87fe0077e f7ee c1fa08 8bf2 }
            // n = 5, score = 200
            //   2bf1                 | sub                 esi, ecx
            //   b87fe0077e           | mov                 eax, 0x7e07e07f
            //   f7ee                 | imul                esi
            //   c1fa08               | sar                 edx, 8
            //   8bf2                 | mov                 esi, edx

        $sequence_7 = { b93c000000 03ce 83c40c c74424241c000000 81f900100000 7e5a }
            // n = 6, score = 200
            //   b93c000000           | mov                 ecx, 0x3c
            //   03ce                 | add                 ecx, esi
            //   83c40c               | add                 esp, 0xc
            //   c74424241c000000     | mov                 dword ptr [esp + 0x24], 0x1c
            //   81f900100000         | cmp                 ecx, 0x1000
            //   7e5a                 | jle                 0x5c

        $sequence_8 = { 02c8 488d05f0f60100 02c9 4002ce }
            // n = 4, score = 100
            //   02c8                 | mov                 eax, dword ptr [ecx + 0x10]
            //   488d05f0f60100       | cmp                 dword ptr [eax + 0x94], 0
            //   02c9                 | add                 cl, al
            //   4002ce               | dec                 eax

        $sequence_9 = { 03c1 89442468 413bc5 7250 }
            // n = 4, score = 100
            //   03c1                 | inc                 ecx
            //   89442468             | movzx               ecx, dl
            //   413bc5               | inc                 edx
            //   7250                 | xor                 dl, byte ptr [ecx + eax]

        $sequence_10 = { 03cd 8908 f6437804 7417 }
            // n = 4, score = 100
            //   03cd                 | inc                 ebx
            //   8908                 | lea                 eax, [ebp + ebp]
            //   f6437804             | inc                 esp
            //   7417                 | mov                 ebp, eax

        $sequence_11 = { 03cf 8908 488b4340 48833800 }
            // n = 4, score = 100
            //   03cf                 | movzx               ecx, cl
            //   8908                 | inc                 edx
            //   488b4340             | mov                 dl, byte ptr [ecx + eax]
            //   48833800             | inc                 ecx

        $sequence_12 = { 017130 83793005 7407 33c0 }
            // n = 4, score = 100
            //   017130               | add                 dword ptr [ecx + 0x30], esi
            //   83793005             | cmp                 dword ptr [ecx + 0x30], 5
            //   7407                 | je                  9
            //   33c0                 | xor                 eax, eax

        $sequence_13 = { 02ca 4402d1 410fb6ca 42321401 }
            // n = 4, score = 100
            //   02ca                 | dec                 eax
            //   4402d1               | cmp                 edi, eax
            //   410fb6ca             | add                 cl, al
            //   42321401             | dec                 eax

        $sequence_14 = { 03ca 0fb6c9 428a1401 4130143b }
            // n = 4, score = 100
            //   03ca                 | mov                 byte ptr [ebx], dl
            //   0fb6c9               | inc                 edx
            //   428a1401             | xor                 byte ptr [ecx + eax], dl
            //   4130143b             | inc                 edx

        $sequence_15 = { 03d0 69d290010000 3bca 740a 418b84b308360400 }
            // n = 5, score = 100
            //   03d0                 | xor                 byte ptr [ebx + edi], dl
            //   69d290010000         | dec                 ecx
            //   3bca                 | inc                 ebx
            //   740a                 | dec                 esp
            //   418b84b308360400     | cmp                 ebx, ebx

    condition:
        7 of them and filesize < 626688
}