rule win_skinnyboy_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.skinnyboy."
        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.skinnyboy"
        malpedia_rule_date = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 03cb 51 ff37 6a08 ff15???????? }
            // n = 5, score = 100
            //   03cb                 | add                 ecx, ebx
            //   51                   | push                ecx
            //   ff37                 | push                dword ptr [edi]
            //   6a08                 | push                8
            //   ff15????????         |                     

        $sequence_1 = { ff30 8945f0 ff36 8975f4 }
            // n = 4, score = 100
            //   ff30                 | push                dword ptr [eax]
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   ff36                 | push                dword ptr [esi]
            //   8975f4               | mov                 dword ptr [ebp - 0xc], esi

        $sequence_2 = { 7d0d 8a441918 888158050110 41 ebe8 8975e0 }
            // n = 6, score = 100
            //   7d0d                 | jge                 0xf
            //   8a441918             | mov                 al, byte ptr [ecx + ebx + 0x18]
            //   888158050110         | mov                 byte ptr [ecx + 0x10010558], al
            //   41                   | inc                 ecx
            //   ebe8                 | jmp                 0xffffffea
            //   8975e0               | mov                 dword ptr [ebp - 0x20], esi

        $sequence_3 = { ffd7 ffd3 6a00 6a00 }
            // n = 4, score = 100
            //   ffd7                 | call                edi
            //   ffd3                 | call                ebx
            //   6a00                 | push                0
            //   6a00                 | push                0

        $sequence_4 = { e8???????? 8b44242c 8b742424 8b5c2428 89442438 }
            // n = 5, score = 100
            //   e8????????           |                     
            //   8b44242c             | mov                 eax, dword ptr [esp + 0x2c]
            //   8b742424             | mov                 esi, dword ptr [esp + 0x24]
            //   8b5c2428             | mov                 ebx, dword ptr [esp + 0x28]
            //   89442438             | mov                 dword ptr [esp + 0x38], eax

        $sequence_5 = { 6a01 56 ff15???????? 8d4c2420 }
            // n = 4, score = 100
            //   6a01                 | push                1
            //   56                   | push                esi
            //   ff15????????         |                     
            //   8d4c2420             | lea                 ecx, [esp + 0x20]

        $sequence_6 = { ffb5e0feffff 6a08 ff15???????? 50 ff15???????? 8bf0 }
            // n = 6, score = 100
            //   ffb5e0feffff         | push                dword ptr [ebp - 0x120]
            //   6a08                 | push                8
            //   ff15????????         |                     
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8bf0                 | mov                 esi, eax

        $sequence_7 = { 833cfdd80b011000 7515 68a00f0000 56 ff15???????? 8934fdd80b0110 }
            // n = 6, score = 100
            //   833cfdd80b011000     | cmp                 dword ptr [edi*8 + 0x10010bd8], 0
            //   7515                 | jne                 0x17
            //   68a00f0000           | push                0xfa0
            //   56                   | push                esi
            //   ff15????????         |                     
            //   8934fdd80b0110       | mov                 dword ptr [edi*8 + 0x10010bd8], esi

        $sequence_8 = { 5f 8908 8b4dfc 8bc6 33cd 5e e8???????? }
            // n = 7, score = 100
            //   5f                   | pop                 edi
            //   8908                 | mov                 dword ptr [eax], ecx
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   8bc6                 | mov                 eax, esi
            //   33cd                 | xor                 ecx, ebp
            //   5e                   | pop                 esi
            //   e8????????           |                     

        $sequence_9 = { 59 eb36 8b8530e5ffff 8b8d14e5ffff 8b048510110110 }
            // n = 5, score = 100
            //   59                   | pop                 ecx
            //   eb36                 | jmp                 0x38
            //   8b8530e5ffff         | mov                 eax, dword ptr [ebp - 0x1ad0]
            //   8b8d14e5ffff         | mov                 ecx, dword ptr [ebp - 0x1aec]
            //   8b048510110110       | mov                 eax, dword ptr [eax*4 + 0x10011110]

    condition:
        7 of them and filesize < 176128
}