rule win_micrass_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        version = "1"
        description = "Detects win.micrass."
        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.micrass"
        malpedia_rule_date = "20230328"
        malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d"
        malpedia_version = "20230407"
        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 = { 8bf9 c1e704 037ddc 33c7 8b7dfc 8145fc4786c861 03f9 }
            // n = 7, score = 100
            //   8bf9                 | mov                 edi, ecx
            //   c1e704               | shl                 edi, 4
            //   037ddc               | add                 edi, dword ptr [ebp - 0x24]
            //   33c7                 | xor                 eax, edi
            //   8b7dfc               | mov                 edi, dword ptr [ebp - 4]
            //   8145fc4786c861       | add                 dword ptr [ebp - 4], 0x61c88647
            //   03f9                 | add                 edi, ecx

        $sequence_1 = { 8b45f4 8b4c1004 c745fc2037efc6 c745f020000000 8bc6 }
            // n = 5, score = 100
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   8b4c1004             | mov                 ecx, dword ptr [eax + edx + 4]
            //   c745fc2037efc6       | mov                 dword ptr [ebp - 4], 0xc6ef3720
            //   c745f020000000       | mov                 dword ptr [ebp - 0x10], 0x20
            //   8bc6                 | mov                 eax, esi

        $sequence_2 = { 8b8514faffff 40 898514faffff 83bd14faffff12 }
            // n = 4, score = 100
            //   8b8514faffff         | mov                 eax, dword ptr [ebp - 0x5ec]
            //   40                   | inc                 eax
            //   898514faffff         | mov                 dword ptr [ebp - 0x5ec], eax
            //   83bd14faffff12       | cmp                 dword ptr [ebp - 0x5ec], 0x12

        $sequence_3 = { 2b34bda0dd4000 c1fe06 8bc7 c1e005 }
            // n = 4, score = 100
            //   2b34bda0dd4000       | sub                 esi, dword ptr [edi*4 + 0x40dda0]
            //   c1fe06               | sar                 esi, 6
            //   8bc7                 | mov                 eax, edi
            //   c1e005               | shl                 eax, 5

        $sequence_4 = { 8bd1 c1fa05 c1e006 030495a0dd4000 eb05 b8???????? }
            // n = 6, score = 100
            //   8bd1                 | mov                 edx, ecx
            //   c1fa05               | sar                 edx, 5
            //   c1e006               | shl                 eax, 6
            //   030495a0dd4000       | add                 eax, dword ptr [edx*4 + 0x40dda0]
            //   eb05                 | jmp                 7
            //   b8????????           |                     

        $sequence_5 = { a3???????? 0f95c0 8b4dfc 5f 5e 33cd }
            // n = 6, score = 100
            //   a3????????           |                     
            //   0f95c0               | setne               al
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   33cd                 | xor                 ecx, ebp

        $sequence_6 = { ff2485ef444000 33c0 838df4fbffffff 8985a0fbffff }
            // n = 4, score = 100
            //   ff2485ef444000       | jmp                 dword ptr [eax*4 + 0x4044ef]
            //   33c0                 | xor                 eax, eax
            //   838df4fbffffff       | or                  dword ptr [ebp - 0x40c], 0xffffffff
            //   8985a0fbffff         | mov                 dword ptr [ebp - 0x460], eax

        $sequence_7 = { ff15???????? 6804010000 57 53 e8???????? 83c40c }
            // n = 6, score = 100
            //   ff15????????         |                     
            //   6804010000           | push                0x104
            //   57                   | push                edi
            //   53                   | push                ebx
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc

        $sequence_8 = { 8d45c4 50 68???????? 56 ff15???????? 85c0 741b }
            // n = 7, score = 100
            //   8d45c4               | lea                 eax, [ebp - 0x3c]
            //   50                   | push                eax
            //   68????????           |                     
            //   56                   | push                esi
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   741b                 | je                  0x1d

        $sequence_9 = { 8d851cfeffff 50 57 ffd6 a3???????? 391d???????? }
            // n = 6, score = 100
            //   8d851cfeffff         | lea                 eax, [ebp - 0x1e4]
            //   50                   | push                eax
            //   57                   | push                edi
            //   ffd6                 | call                esi
            //   a3????????           |                     
            //   391d????????         |                     

    condition:
        7 of them and filesize < 163840
}