rule win_gearshift_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-12-06"
        version = "1"
        description = "Detects win.gearshift."
        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.gearshift"
        malpedia_rule_date = "20231130"
        malpedia_hash = "fc8a0e9f343f6d6ded9e7df1a64dac0cc68d7351"
        malpedia_version = "20230808"
        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 = { 4881c4c0000000 5f c3 85c0 0f85a9000000 }
            // n = 5, score = 200
            //   4881c4c0000000       | dec                 eax
            //   5f                   | mov                 dword ptr [esp + 0x78], esi
            //   c3                   | ret                 
            //   85c0                 | inc                 ecx
            //   0f85a9000000         | inc                 edx

        $sequence_1 = { 4d8bde 4d2b5d30 0f84a1000000 488b4500 488b5d08 }
            // n = 5, score = 200
            //   4d8bde               | dec                 ebp
            //   4d2b5d30             | mov                 ebp, ecx
            //   0f84a1000000         | dec                 ebp
            //   488b4500             | mov                 edi, eax
            //   488b5d08             | inc                 ecx

        $sequence_2 = { 4883ec28 48833d????????00 740a b801000000 4883c428 c3 488d0dc9a80000 }
            // n = 7, score = 200
            //   4883ec28             | mov                 dword ptr [eax], ecx
            //   48833d????????00     |                     
            //   740a                 | jmp                 0x8ca
            //   b801000000           | dec                 eax
            //   4883c428             | arpl                word ptr [esp + 0x34], cx
            //   c3                   | dec                 eax
            //   488d0dc9a80000       | mov                 eax, dword ptr [esp + 0x20]

        $sequence_3 = { 4823f1 66413b7806 0f83ce000000 48895c2448 4c89642450 4c8d25566a0300 4a8d5c003c }
            // n = 7, score = 200
            //   4823f1               | ret                 
            //   66413b7806           | xor                 al, al
            //   0f83ce000000         | test                edx, edx
            //   48895c2448           | jbe                 0x509
            //   4c89642450           | dec                 eax
            //   4c8d25566a0300       | lea                 ebp, [ecx - 0x7ff80000]
            //   4a8d5c003c           | jmp                 0x50e

        $sequence_4 = { 83c8ff e9???????? 4c8bfb 4c8be3 488d05363c0300 49c1fc05 }
            // n = 6, score = 200
            //   83c8ff               | mov                 dword ptr [ebp + 0x18], esp
            //   e9????????           |                     
            //   4c8bfb               | mov                 eax, dword ptr [esp + 0x70]
            //   4c8be3               | dec                 eax
            //   488d05363c0300       | mov                 eax, dword ptr [esp + 0x60]
            //   49c1fc05             | mov                 eax, edi

        $sequence_5 = { 4885c0 0f8418010000 4c8d442470 41b910010000 488bd0 488bcb 48897c2420 }
            // n = 7, score = 200
            //   4885c0               | dec                 esp
            //   0f8418010000         | mov                 eax, dword ptr [eax + 0x28]
            //   4c8d442470           | dec                 ecx
            //   41b910010000         | cmp                 ecx, eax
            //   488bd0               | jae                 0xd3f
            //   488bcb               | mov                 dword ptr [esp + 8], ecx
            //   48897c2420           | dec                 eax

        $sequence_6 = { 488bd8 ff9688000000 4c8bc3 33d2 488bc8 8947f8 ff96a8000000 }
            // n = 7, score = 200
            //   488bd8               | mov                 ecx, ebx
            //   ff9688000000         | dec                 eax
            //   4c8bc3               | mov                 eax, ebx
            //   33d2                 | dec                 eax
            //   488bc8               | lea                 edx, [0xab37]
            //   8947f8               | dec                 eax
            //   ff96a8000000         | sar                 eax, 5

        $sequence_7 = { 7522 48ffc1 498d0408 493bc3 7cec 4963c2 4803c6 }
            // n = 7, score = 200
            //   7522                 | mov                 ebp, eax
            //   48ffc1               | mov                 ebx, edx
            //   498d0408             | dec                 eax
            //   493bc3               | sub                 esp, 0x150
            //   7cec                 | dec                 esp
            //   4963c2               | mov                 esp, ecx
            //   4803c6               | dec                 eax

        $sequence_8 = { 4533c0 33d2 498bcc 44896c2428 48897c2420 ff15???????? ba01000000 }
            // n = 7, score = 200
            //   4533c0               | mov                 eax, dword ptr [esp + 0x28]
            //   33d2                 | inc                 esi
            //   498bcc               | dec                 eax
            //   44896c2428           | add                 ebx, 4
            //   48897c2420           | mov                 dword ptr [ebx - 4], eax
            //   ff15????????         |                     
            //   ba01000000           | dec                 eax

        $sequence_9 = { 0fb7d1 eb09 488b4508 488d540102 }
            // n = 4, score = 200
            //   0fb7d1               | int3                
            //   eb09                 | int3                
            //   488b4508             | int3                
            //   488d540102           | int3                

    condition:
        7 of them and filesize < 540672
}

rule win_gearshift_w0 {
    meta:
        author = "Bundesamt fuer Verfassungsschutz"
        source = "https://www.verfassungsschutz.de/download/anlage-2019-12-bfv-cyber-brief-2019-01.txt"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.gearshift"
        malpedia_version = "20191207"
        malpedia_sharing = "TLP:WHITE"
        malpedia_license = ""
    strings:
        $b1 = { 4C 8D 41 24 33 D2 B9 03 00 1F 00 FF 9? F8 00 00 00 48 85 C0 74 }
        $b2 = { 4C 8B 4? 08 BA 01 00 00 00 49 8B C? FF D0 85 C0 [2-6] C7 4? 1C 01 00 00 00 B8 01 00 00 00 }
        $b3 = { 8B 4B E4 8B 53 EC 41 B8 00 40 00 00 4? 0B C? FF 9? B8 00 00 00 EB }
    condition:
        (2 of ($b*))
}