rule win_vskimmer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.vskimmer."
        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.vskimmer"
        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 = { 895dfc e8???????? 6a01 e8???????? 83c420 53 6a01 }
            // n = 7, score = 100
            //   895dfc               | mov                 dword ptr [ebp - 4], ebx
            //   e8????????           |                     
            //   6a01                 | push                1
            //   e8????????           |                     
            //   83c420               | add                 esp, 0x20
            //   53                   | push                ebx
            //   6a01                 | push                1

        $sequence_1 = { 47 3810 751f ebe7 3b7d18 }
            // n = 5, score = 100
            //   47                   | inc                 edi
            //   3810                 | cmp                 byte ptr [eax], dl
            //   751f                 | jne                 0x21
            //   ebe7                 | jmp                 0xffffffe9
            //   3b7d18               | cmp                 edi, dword ptr [ebp + 0x18]

        $sequence_2 = { 53 8b1f 8d4301 56 8b7508 8945f8 8b4614 }
            // n = 7, score = 100
            //   53                   | push                ebx
            //   8b1f                 | mov                 ebx, dword ptr [edi]
            //   8d4301               | lea                 eax, [ebx + 1]
            //   56                   | push                esi
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]
            //   8945f8               | mov                 dword ptr [ebp - 8], eax
            //   8b4614               | mov                 eax, dword ptr [esi + 0x14]

        $sequence_3 = { 85c0 0f84ba000000 57 8b3d???????? 8d45ec 50 }
            // n = 6, score = 100
            //   85c0                 | test                eax, eax
            //   0f84ba000000         | je                  0xc0
            //   57                   | push                edi
            //   8b3d????????         |                     
            //   8d45ec               | lea                 eax, [ebp - 0x14]
            //   50                   | push                eax

        $sequence_4 = { ff15???????? 50 ff15???????? 8d45cc 50 68???????? 6a00 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8d45cc               | lea                 eax, [ebp - 0x34]
            //   50                   | push                eax
            //   68????????           |                     
            //   6a00                 | push                0

        $sequence_5 = { 3bf3 7408 8b451c 8906 897e14 }
            // n = 5, score = 100
            //   3bf3                 | cmp                 esi, ebx
            //   7408                 | je                  0xa
            //   8b451c               | mov                 eax, dword ptr [ebp + 0x1c]
            //   8906                 | mov                 dword ptr [esi], eax
            //   897e14               | mov                 dword ptr [esi + 0x14], edi

        $sequence_6 = { 59 50 57 68???????? 8d8d38f7ffff e8???????? ffb5c4f6ffff }
            // n = 7, score = 100
            //   59                   | pop                 ecx
            //   50                   | push                eax
            //   57                   | push                edi
            //   68????????           |                     
            //   8d8d38f7ffff         | lea                 ecx, [ebp - 0x8c8]
            //   e8????????           |                     
            //   ffb5c4f6ffff         | push                dword ptr [ebp - 0x93c]

        $sequence_7 = { 836df804 83c604 3b45f4 0f8253ffffff }
            // n = 4, score = 100
            //   836df804             | sub                 dword ptr [ebp - 8], 4
            //   83c604               | add                 esi, 4
            //   3b45f4               | cmp                 eax, dword ptr [ebp - 0xc]
            //   0f8253ffffff         | jb                  0xffffff59

        $sequence_8 = { 6a01 8d8dc8fcffff e8???????? e8???????? c3 6a08 }
            // n = 6, score = 100
            //   6a01                 | push                1
            //   8d8dc8fcffff         | lea                 ecx, [ebp - 0x338]
            //   e8????????           |                     
            //   e8????????           |                     
            //   c3                   | ret                 
            //   6a08                 | push                8

        $sequence_9 = { 751c 85c9 7508 c70703000000 eb37 83f901 7504 }
            // n = 7, score = 100
            //   751c                 | jne                 0x1e
            //   85c9                 | test                ecx, ecx
            //   7508                 | jne                 0xa
            //   c70703000000         | mov                 dword ptr [edi], 3
            //   eb37                 | jmp                 0x39
            //   83f901               | cmp                 ecx, 1
            //   7504                 | jne                 6

    condition:
        7 of them and filesize < 376832
}