rule win_gemcutter_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.gemcutter."
        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.gemcutter"
        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 = { e8???????? 83c40c 8d45f0 c745d801000000 668975dc 50 8d45ac }
            // n = 7, score = 100
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   8d45f0               | lea                 eax, [ebp - 0x10]
            //   c745d801000000       | mov                 dword ptr [ebp - 0x28], 1
            //   668975dc             | mov                 word ptr [ebp - 0x24], si
            //   50                   | push                eax
            //   8d45ac               | lea                 eax, [ebp - 0x54]

        $sequence_1 = { 6802000080 ff15???????? 837d0c01 ff7508 }
            // n = 4, score = 100
            //   6802000080           | push                0x80000002
            //   ff15????????         |                     
            //   837d0c01             | cmp                 dword ptr [ebp + 0xc], 1
            //   ff7508               | push                dword ptr [ebp + 8]

        $sequence_2 = { e8???????? 83c424 8b3d???????? 56 33f6 56 56 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   83c424               | add                 esp, 0x24
            //   8b3d????????         |                     
            //   56                   | push                esi
            //   33f6                 | xor                 esi, esi
            //   56                   | push                esi
            //   56                   | push                esi

        $sequence_3 = { ff15???????? 8d45f0 50 ffd7 8d85f0fdffff 50 8d85f0fcffff }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   8d45f0               | lea                 eax, [ebp - 0x10]
            //   50                   | push                eax
            //   ffd7                 | call                edi
            //   8d85f0fdffff         | lea                 eax, [ebp - 0x210]
            //   50                   | push                eax
            //   8d85f0fcffff         | lea                 eax, [ebp - 0x310]

        $sequence_4 = { 68???????? 50 e8???????? 8d85f0fdffff 6a2e }
            // n = 5, score = 100
            //   68????????           |                     
            //   50                   | push                eax
            //   e8????????           |                     
            //   8d85f0fdffff         | lea                 eax, [ebp - 0x210]
            //   6a2e                 | push                0x2e

        $sequence_5 = { 50 ffd7 8d85f0f8ffff 6800040000 50 53 ff15???????? }
            // n = 7, score = 100
            //   50                   | push                eax
            //   ffd7                 | call                edi
            //   8d85f0f8ffff         | lea                 eax, [ebp - 0x710]
            //   6800040000           | push                0x400
            //   50                   | push                eax
            //   53                   | push                ebx
            //   ff15????????         |                     

        $sequence_6 = { 6a2e 50 ff15???????? 8818 8d85f0f8ffff 6a2e 50 }
            // n = 7, score = 100
            //   6a2e                 | push                0x2e
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8818                 | mov                 byte ptr [eax], bl
            //   8d85f0f8ffff         | lea                 eax, [ebp - 0x710]
            //   6a2e                 | push                0x2e
            //   50                   | push                eax

        $sequence_7 = { 53 56 56 56 a3???????? ffd7 56 }
            // n = 7, score = 100
            //   53                   | push                ebx
            //   56                   | push                esi
            //   56                   | push                esi
            //   56                   | push                esi
            //   a3????????           |                     
            //   ffd7                 | call                edi
            //   56                   | push                esi

        $sequence_8 = { 7438 50 ff15???????? ff35???????? }
            // n = 4, score = 100
            //   7438                 | je                  0x3a
            //   50                   | push                eax
            //   ff15????????         |                     
            //   ff35????????         |                     

        $sequence_9 = { 59 50 ff15???????? 0c06 50 8d85f0fdffff }
            // n = 6, score = 100
            //   59                   | pop                 ecx
            //   50                   | push                eax
            //   ff15????????         |                     
            //   0c06                 | or                  al, 6
            //   50                   | push                eax
            //   8d85f0fdffff         | lea                 eax, [ebp - 0x210]

    condition:
        7 of them and filesize < 40960
}