rule win_grillmark_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.grillmark."
        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.grillmark"
        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 = { 682c020000 6a40 ff15???????? 8bf8 56 }
            // n = 5, score = 300
            //   682c020000           | push                0x22c
            //   6a40                 | push                0x40
            //   ff15????????         |                     
            //   8bf8                 | mov                 edi, eax
            //   56                   | push                esi

        $sequence_1 = { 33c0 8dbdbdf8ffff 80a5bcf4ffff00 f3ab 66ab aa 8bca }
            // n = 7, score = 300
            //   33c0                 | xor                 eax, eax
            //   8dbdbdf8ffff         | lea                 edi, [ebp - 0x743]
            //   80a5bcf4ffff00       | and                 byte ptr [ebp - 0xb44], 0
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   aa                   | stosb               byte ptr es:[edi], al
            //   8bca                 | mov                 ecx, edx

        $sequence_2 = { 7522 ff75c8 e8???????? 59 ff45e0 837de03c 756c }
            // n = 7, score = 300
            //   7522                 | jne                 0x24
            //   ff75c8               | push                dword ptr [ebp - 0x38]
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   ff45e0               | inc                 dword ptr [ebp - 0x20]
            //   837de03c             | cmp                 dword ptr [ebp - 0x20], 0x3c
            //   756c                 | jne                 0x6e

        $sequence_3 = { 8975e4 6a09 ab 59 8d7dc0 }
            // n = 5, score = 300
            //   8975e4               | mov                 dword ptr [ebp - 0x1c], esi
            //   6a09                 | push                9
            //   ab                   | stosd               dword ptr es:[edi], eax
            //   59                   | pop                 ecx
            //   8d7dc0               | lea                 edi, [ebp - 0x40]

        $sequence_4 = { be???????? 50 ff35???????? 56 e8???????? 83c41c }
            // n = 6, score = 300
            //   be????????           |                     
            //   50                   | push                eax
            //   ff35????????         |                     
            //   56                   | push                esi
            //   e8????????           |                     
            //   83c41c               | add                 esp, 0x1c

        $sequence_5 = { 68???????? eb0d 8d45fc 50 6a01 }
            // n = 5, score = 300
            //   68????????           |                     
            //   eb0d                 | jmp                 0xf
            //   8d45fc               | lea                 eax, [ebp - 4]
            //   50                   | push                eax
            //   6a01                 | push                1

        $sequence_6 = { 8dbdfdfeffff 889dfcfeffff 53 f3ab 66ab aa 8d85fcfeffff }
            // n = 7, score = 300
            //   8dbdfdfeffff         | lea                 edi, [ebp - 0x103]
            //   889dfcfeffff         | mov                 byte ptr [ebp - 0x104], bl
            //   53                   | push                ebx
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   aa                   | stosb               byte ptr es:[edi], al
            //   8d85fcfeffff         | lea                 eax, [ebp - 0x104]

        $sequence_7 = { 68???????? 50 e8???????? 57 e8???????? 83c424 }
            // n = 6, score = 300
            //   68????????           |                     
            //   50                   | push                eax
            //   e8????????           |                     
            //   57                   | push                edi
            //   e8????????           |                     
            //   83c424               | add                 esp, 0x24

        $sequence_8 = { 03c6 46 e8???????? 3bf0 59 72c5 8b45fc }
            // n = 7, score = 300
            //   03c6                 | add                 eax, esi
            //   46                   | inc                 esi
            //   e8????????           |                     
            //   3bf0                 | cmp                 esi, eax
            //   59                   | pop                 ecx
            //   72c5                 | jb                  0xffffffc7
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]

        $sequence_9 = { 8b55f4 ff45f0 8345f404 893a ff45f8 880f 47 }
            // n = 7, score = 300
            //   8b55f4               | mov                 edx, dword ptr [ebp - 0xc]
            //   ff45f0               | inc                 dword ptr [ebp - 0x10]
            //   8345f404             | add                 dword ptr [ebp - 0xc], 4
            //   893a                 | mov                 dword ptr [edx], edi
            //   ff45f8               | inc                 dword ptr [ebp - 8]
            //   880f                 | mov                 byte ptr [edi], cl
            //   47                   | inc                 edi

    condition:
        7 of them and filesize < 212992
}