rule win_sharpknot_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.sharpknot."
        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.sharpknot"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { 8b4514 f6c303 7509 8b0c85e8dc4000 eb07 8b0c851cdd4000 }
            // n = 6, score = 100
            //   8b4514               | mov                 eax, dword ptr [ebp + 0x14]
            //   f6c303               | test                bl, 3
            //   7509                 | jne                 0xb
            //   8b0c85e8dc4000       | mov                 ecx, dword ptr [eax*4 + 0x40dce8]
            //   eb07                 | jmp                 9
            //   8b0c851cdd4000       | mov                 ecx, dword ptr [eax*4 + 0x40dd1c]

        $sequence_1 = { 7508 660fb6b680f74400 663bfe 751f 6685ff 742d }
            // n = 6, score = 100
            //   7508                 | jne                 0xa
            //   660fb6b680f74400     | movzx               si, byte ptr [esi + 0x44f780]
            //   663bfe               | cmp                 di, si
            //   751f                 | jne                 0x21
            //   6685ff               | test                di, di
            //   742d                 | je                  0x2f

        $sequence_2 = { 55 50 8bcb 89442428 e8???????? }
            // n = 5, score = 100
            //   55                   | push                ebp
            //   50                   | push                eax
            //   8bcb                 | mov                 ecx, ebx
            //   89442428             | mov                 dword ptr [esp + 0x28], eax
            //   e8????????           |                     

        $sequence_3 = { 50 2bcd b8abaaaa2a f7e9 c1fa02 8bca }
            // n = 6, score = 100
            //   50                   | push                eax
            //   2bcd                 | sub                 ecx, ebp
            //   b8abaaaa2a           | mov                 eax, 0x2aaaaaab
            //   f7e9                 | imul                ecx
            //   c1fa02               | sar                 edx, 2
            //   8bca                 | mov                 ecx, edx

        $sequence_4 = { 8d4c2420 89442414 51 6a01 50 8bcb e8???????? }
            // n = 7, score = 100
            //   8d4c2420             | lea                 ecx, [esp + 0x20]
            //   89442414             | mov                 dword ptr [esp + 0x14], eax
            //   51                   | push                ecx
            //   6a01                 | push                1
            //   50                   | push                eax
            //   8bcb                 | mov                 ecx, ebx
            //   e8????????           |                     

        $sequence_5 = { 83c448 8d442404 56 68???????? 50 e8???????? }
            // n = 6, score = 100
            //   83c448               | add                 esp, 0x48
            //   8d442404             | lea                 eax, [esp + 4]
            //   56                   | push                esi
            //   68????????           |                     
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_6 = { 50 eb24 6a00 8d4c2414 }
            // n = 4, score = 100
            //   50                   | push                eax
            //   eb24                 | jmp                 0x26
            //   6a00                 | push                0
            //   8d4c2414             | lea                 ecx, [esp + 0x14]

        $sequence_7 = { 7522 8d44240c 50 e8???????? 8bf0 83c408 85f6 }
            // n = 7, score = 100
            //   7522                 | jne                 0x24
            //   8d44240c             | lea                 eax, [esp + 0xc]
            //   50                   | push                eax
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax
            //   83c408               | add                 esp, 8
            //   85f6                 | test                esi, esi

        $sequence_8 = { 85c0 742e 8d44243c 68???????? 50 ff15???????? }
            // n = 6, score = 100
            //   85c0                 | test                eax, eax
            //   742e                 | je                  0x30
            //   8d44243c             | lea                 eax, [esp + 0x3c]
            //   68????????           |                     
            //   50                   | push                eax
            //   ff15????????         |                     

        $sequence_9 = { 0fb6c3 f68081f8440004 741a 8a4601 46 84c0 741d }
            // n = 7, score = 100
            //   0fb6c3               | movzx               eax, bl
            //   f68081f8440004       | test                byte ptr [eax + 0x44f881], 4
            //   741a                 | je                  0x1c
            //   8a4601               | mov                 al, byte ptr [esi + 1]
            //   46                   | inc                 esi
            //   84c0                 | test                al, al
            //   741d                 | je                  0x1f

    condition:
        7 of them and filesize < 1032192
}

rule win_sharpknot_w0 {
    meta:
        author = "NCCIC Partner"
        source = "NCCIC Partner"
        date = "2017-12-12"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.sharpknot"
        malpedia_version = "20180413"
        malpedia_sharing = "TLP:WHITE"
        malpedia_license = ""
    strings:
        $mbr_code = { 33 C0 8E D0 BC 00 7C FB 50 07 50 1F FC BE 5D 7C 33 C9 41 81 F9 00 ?? 74 24 B4 43 B0 00 CD 13 FE C2 80 FA 84 7C F3 B2 80 BF 65 7C 81 05 00 04 83 55 02 00 83 55 04 00 83 55 06 00 EB D5 BE 4D 7C B4 43 B0 00 CD 13 33 C9 BE 5D 7C EB C5 }
        $controlServiceFoundlnBoth = { 83 EC 1C 57 68 3F 00 0F 00 6A 00 6A 00 FF 15 ?? ?? ?? ?? 8B F8 85 FF 74 44 8B 44 24 24 53 56 6A 24 50 57 FF 15 ?? ?? ?? ?? 8B 1D ?? ?? ?? ?? 8B F0 85 F6 74 1C 8D 4C 24 0C 51 6A 01 56 FF 15 ?? ?? ?? ?? 68 E8 03 00 00 FF 15 ?? ?? ?? ?? 56 FF D3 57 FF D3 5E 5B 33 C0 5F 83 C4 1C C3 33 C0 5F 83 C4 1C C3 }
    condition:
    any of them
}