rule win_rustock_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        version = "1"
        description = "Detects win.rustock."
        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.rustock"
        malpedia_rule_date = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 8b4c0b78 01d9 8b5120 01da 8b3a 01df 57 }
            // n = 7, score = 100
            //   8b4c0b78             | mov                 ecx, dword ptr [ebx + ecx + 0x78]
            //   01d9                 | add                 ecx, ebx
            //   8b5120               | mov                 edx, dword ptr [ecx + 0x20]
            //   01da                 | add                 edx, ebx
            //   8b3a                 | mov                 edi, dword ptr [edx]
            //   01df                 | add                 edi, ebx
            //   57                   | push                edi

        $sequence_1 = { 8b048560320401 8bcf 83e11f 8d04c8 8b0b 8908 }
            // n = 6, score = 100
            //   8b048560320401       | mov                 eax, dword ptr [eax*4 + 0x1043260]
            //   8bcf                 | mov                 ecx, edi
            //   83e11f               | and                 ecx, 0x1f
            //   8d04c8               | lea                 eax, [eax + ecx*8]
            //   8b0b                 | mov                 ecx, dword ptr [ebx]
            //   8908                 | mov                 dword ptr [eax], ecx

        $sequence_2 = { 53 52 56 31fe 83f0ff 29db 8b0d???????? }
            // n = 7, score = 100
            //   53                   | push                ebx
            //   52                   | push                edx
            //   56                   | push                esi
            //   31fe                 | xor                 esi, edi
            //   83f0ff               | xor                 eax, 0xffffffff
            //   29db                 | sub                 ebx, ebx
            //   8b0d????????         |                     

        $sequence_3 = { 837c240c00 7514 ff742404 c705????????01000000 e8???????? 59 }
            // n = 6, score = 100
            //   837c240c00           | cmp                 dword ptr [esp + 0xc], 0
            //   7514                 | jne                 0x16
            //   ff742404             | push                dword ptr [esp + 4]
            //   c705????????01000000     |     
            //   e8????????           |                     
            //   59                   | pop                 ecx

        $sequence_4 = { 6809020000 53 e8???????? 8bf0 f7de 1bf6 f7de }
            // n = 7, score = 100
            //   6809020000           | push                0x209
            //   53                   | push                ebx
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax
            //   f7de                 | neg                 esi
            //   1bf6                 | sbb                 esi, esi
            //   f7de                 | neg                 esi

        $sequence_5 = { e68a e565 f9 17 }
            // n = 4, score = 100
            //   e68a                 | out                 0x8a, al
            //   e565                 | in                  eax, 0x65
            //   f9                   | stc                 
            //   17                   | pop                 ss

        $sequence_6 = { ffd6 68e1020000 57 a3???????? ffd6 }
            // n = 5, score = 100
            //   ffd6                 | call                esi
            //   68e1020000           | push                0x2e1
            //   57                   | push                edi
            //   a3????????           |                     
            //   ffd6                 | call                esi

        $sequence_7 = { 8b0d???????? 030d???????? 09f3 ff35???????? }
            // n = 4, score = 100
            //   8b0d????????         |                     
            //   030d????????         |                     
            //   09f3                 | or                  ebx, esi
            //   ff35????????         |                     

        $sequence_8 = { 8b15???????? 8d1432 21c1 ff35???????? 5a b9906a0100 83f0ff }
            // n = 7, score = 100
            //   8b15????????         |                     
            //   8d1432               | lea                 edx, [edx + esi]
            //   21c1                 | and                 ecx, eax
            //   ff35????????         |                     
            //   5a                   | pop                 edx
            //   b9906a0100           | mov                 ecx, 0x16a90
            //   83f0ff               | xor                 eax, 0xffffffff

        $sequence_9 = { 29c2 8d801c3367d0 8d6424fc 891424 8f07 68???????? }
            // n = 6, score = 100
            //   29c2                 | sub                 edx, eax
            //   8d801c3367d0         | lea                 eax, [eax - 0x2f98cce4]
            //   8d6424fc             | lea                 esp, [esp - 4]
            //   891424               | mov                 dword ptr [esp], edx
            //   8f07                 | pop                 dword ptr [edi]
            //   68????????           |                     

    condition:
        7 of them and filesize < 565248
}