rule win_webc2_yahoo_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.webc2_yahoo."
        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.webc2_yahoo"
        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 = { 53 e8???????? 83c424 8d85fcfeffff 56 50 68???????? }
            // n = 7, score = 100
            //   53                   | push                ebx
            //   e8????????           |                     
            //   83c424               | add                 esp, 0x24
            //   8d85fcfeffff         | lea                 eax, [ebp - 0x104]
            //   56                   | push                esi
            //   50                   | push                eax
            //   68????????           |                     

        $sequence_1 = { eb06 8b4518 802000 5f 5e }
            // n = 5, score = 100
            //   eb06                 | jmp                 8
            //   8b4518               | mov                 eax, dword ptr [ebp + 0x18]
            //   802000               | and                 byte ptr [eax], 0
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_2 = { f3ab 66ab aa 8d85f0fdffff 50 53 ff15???????? }
            // n = 7, score = 100
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   aa                   | stosb               byte ptr es:[edi], al
            //   8d85f0fdffff         | lea                 eax, [ebp - 0x210]
            //   50                   | push                eax
            //   53                   | push                ebx
            //   ff15????????         |                     

        $sequence_3 = { ffb69c841e00 ff15???????? 85c0 53 74b6 }
            // n = 5, score = 100
            //   ffb69c841e00         | push                dword ptr [esi + 0x1e849c]
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   53                   | push                ebx
            //   74b6                 | je                  0xffffffb8

        $sequence_4 = { c745f800040000 53 e8???????? 8b7d08 57 e8???????? 8bf0 }
            // n = 7, score = 100
            //   c745f800040000       | mov                 dword ptr [ebp - 8], 0x400
            //   53                   | push                ebx
            //   e8????????           |                     
            //   8b7d08               | mov                 edi, dword ptr [ebp + 8]
            //   57                   | push                edi
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax

        $sequence_5 = { 6a64 5b 53 e8???????? }
            // n = 4, score = 100
            //   6a64                 | push                0x64
            //   5b                   | pop                 ebx
            //   53                   | push                ebx
            //   e8????????           |                     

        $sequence_6 = { 888614e75e00 48 46 83f861 7df3 c686????????40 }
            // n = 6, score = 100
            //   888614e75e00         | mov                 byte ptr [esi + 0x5ee714], al
            //   48                   | dec                 eax
            //   46                   | inc                 esi
            //   83f861               | cmp                 eax, 0x61
            //   7df3                 | jge                 0xfffffff5
            //   c686????????40       |                     

        $sequence_7 = { 7403 56 ffd7 6a01 58 5f }
            // n = 6, score = 100
            //   7403                 | je                  5
            //   56                   | push                esi
            //   ffd7                 | call                edi
            //   6a01                 | push                1
            //   58                   | pop                 eax
            //   5f                   | pop                 edi

        $sequence_8 = { 46 33c9 53 c686????????23 c686????????7c }
            // n = 5, score = 100
            //   46                   | inc                 esi
            //   33c9                 | xor                 ecx, ecx
            //   53                   | push                ebx
            //   c686????????23       |                     
            //   c686????????7c       |                     

        $sequence_9 = { 8945e4 e8???????? 59 53 ff75e4 }
            // n = 5, score = 100
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   53                   | push                ebx
            //   ff75e4               | push                dword ptr [ebp - 0x1c]

    condition:
        7 of them and filesize < 8060928
}