rule win_backspace_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.backspace."
        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.backspace"
        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 = { 56 e8???????? 59 6a05 56 ffd7 50 }
            // n = 7, score = 100
            //   56                   | push                esi
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   6a05                 | push                5
            //   56                   | push                esi
            //   ffd7                 | call                edi
            //   50                   | push                eax

        $sequence_1 = { ac 90 d1e8 90 745f 90 }
            // n = 6, score = 100
            //   ac                   | lodsb               al, byte ptr [esi]
            //   90                   | nop                 
            //   d1e8                 | shr                 eax, 1
            //   90                   | nop                 
            //   745f                 | je                  0x61
            //   90                   | nop                 

        $sequence_2 = { 6a2f 50 ff15???????? bf???????? 8d9c3574faffff 57 53 }
            // n = 7, score = 100
            //   6a2f                 | push                0x2f
            //   50                   | push                eax
            //   ff15????????         |                     
            //   bf????????           |                     
            //   8d9c3574faffff       | lea                 ebx, [ebp + esi - 0x58c]
            //   57                   | push                edi
            //   53                   | push                ebx

        $sequence_3 = { 56 e8???????? 83c424 68???????? 56 e8???????? }
            // n = 6, score = 100
            //   56                   | push                esi
            //   e8????????           |                     
            //   83c424               | add                 esp, 0x24
            //   68????????           |                     
            //   56                   | push                esi
            //   e8????????           |                     

        $sequence_4 = { 50 8d4701 56 50 ffd3 85c0 }
            // n = 6, score = 100
            //   50                   | push                eax
            //   8d4701               | lea                 eax, [edi + 1]
            //   56                   | push                esi
            //   50                   | push                eax
            //   ffd3                 | call                ebx
            //   85c0                 | test                eax, eax

        $sequence_5 = { a3???????? 7510 ff35???????? ff15???????? 33c0 eb02 }
            // n = 6, score = 100
            //   a3????????           |                     
            //   7510                 | jne                 0x12
            //   ff35????????         |                     
            //   ff15????????         |                     
            //   33c0                 | xor                 eax, eax
            //   eb02                 | jmp                 4

        $sequence_6 = { 8b0d???????? 69c90c020000 83b96464400000 0f8591000000 }
            // n = 4, score = 100
            //   8b0d????????         |                     
            //   69c90c020000         | imul                ecx, ecx, 0x20c
            //   83b96464400000       | cmp                 dword ptr [ecx + 0x406464], 0
            //   0f8591000000         | jne                 0x97

        $sequence_7 = { 8b0d???????? 03c1 8078fe3a 750a 8078ff5c 0f8495000000 8d8500feffff }
            // n = 7, score = 100
            //   8b0d????????         |                     
            //   03c1                 | add                 eax, ecx
            //   8078fe3a             | cmp                 byte ptr [eax - 2], 0x3a
            //   750a                 | jne                 0xc
            //   8078ff5c             | cmp                 byte ptr [eax - 1], 0x5c
            //   0f8495000000         | je                  0x9b
            //   8d8500feffff         | lea                 eax, [ebp - 0x200]

        $sequence_8 = { e8???????? 83c41c 8d5c0301 ff15???????? b980ee3600 33d2 8bf9 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   83c41c               | add                 esp, 0x1c
            //   8d5c0301             | lea                 ebx, [ebx + eax + 1]
            //   ff15????????         |                     
            //   b980ee3600           | mov                 ecx, 0x36ee80
            //   33d2                 | xor                 edx, edx
            //   8bf9                 | mov                 edi, ecx

        $sequence_9 = { 57 50 ffd6 83c418 85db }
            // n = 5, score = 100
            //   57                   | push                edi
            //   50                   | push                eax
            //   ffd6                 | call                esi
            //   83c418               | add                 esp, 0x18
            //   85db                 | test                ebx, ebx

    condition:
        7 of them and filesize < 131072
}