rule win_nightsky_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.nightsky."
        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.nightsky"
        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 = { 4d03c0 498b17 488bc8 e8???????? 4c8b5b08 488b03 6642892c58 }
            // n = 7, score = 100
            //   4d03c0               | mov                 bh, 0xf5
            //   498b17               | inc                 ecx
            //   488bc8               | push                ebx
            //   e8????????           |                     
            //   4c8b5b08             | push                ebx
            //   488b03               | not                 si
            //   6642892c58           | mov                 si, 0x330d

        $sequence_1 = { e8???????? 488bfb 4803ff 4c8d2d2d000100 49837cfd0000 7404 8bc6 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   488bfb               | dec                 eax
            //   4803ff               | mov                 ecx, ebp
            //   4c8d2d2d000100       | dec                 esp
            //   49837cfd0000         | mov                 eax, esi
            //   7404                 | xor                 edx, edx
            //   8bc6                 | test                eax, eax

        $sequence_2 = { 498b4c2408 48894b08 48ffc1 b802000000 48f7e1 490f40c5 }
            // n = 6, score = 100
            //   498b4c2408           | rol                 dx, cl
            //   48894b08             | dec                 eax
            //   48ffc1               | lea                 eax, [esp + 0x50]
            //   b802000000           | dec                 ebp
            //   48f7e1               | sub                 eax, ecx
            //   490f40c5             | dec                 eax

        $sequence_3 = { 4983fc07 400f97c7 4883c701 745c 498b4508 498b5d18 4c8d4c2420 }
            // n = 7, score = 100
            //   4983fc07             | lea                 edx, [0xa97a]
            //   400f97c7             | dec                 eax
            //   4883c701             | mov                 edi, eax
            //   745c                 | dec                 eax
            //   498b4508             | test                eax, eax
            //   498b5d18             | je                  0xbce
            //   4c8d4c2420           | dec                 eax

        $sequence_4 = { 420fb68c22e0b10400 440bc1 410fb6c9 41c1e008 420fb68c2180af0400 }
            // n = 5, score = 100
            //   420fb68c22e0b10400     | lea    ecx, [ebx + ebx*4]
            //   440bc1               | jmp                 0x3ae
            //   410fb6c9             | dec                 ebp
            //   41c1e008             | test                eax, eax
            //   420fb68c2180af0400     | jne    0x3ae

        $sequence_5 = { 488b88c0000000 488d05d6400100 395914 4a8b0cf0 498b0c0f }
            // n = 5, score = 100
            //   488b88c0000000       | inc                 ecx
            //   488d05d6400100       | push                edi
            //   395914               | dec                 eax
            //   4a8b0cf0             | mov                 ebp, esp
            //   498b0c0f             | dec                 eax

        $sequence_6 = { 41d3e1 4402c0 488bfc 4881ec80010000 f9 66452bc7 4881e4f0ffffff }
            // n = 7, score = 100
            //   41d3e1               | dec                 eax
            //   4402c0               | shrd                ebp, ebp, 0x3e
            //   488bfc               | xor                 dword ptr [esp], ecx
            //   4881ec80010000       | pop                 ebp
            //   f9                   | inc                 eax
            //   66452bc7             | cmp                 al, bh
            //   4881e4f0ffffff       | cmp                 bh, 0xe1

        $sequence_7 = { 4889442428 488d057c130100 4889442420 4c8b4c2450 4c8b442458 488b542460 33c9 }
            // n = 7, score = 100
            //   4889442428           | cmp                 al, cl
            //   488d057c130100       | dec                 eax
            //   4889442420           | mov                 esi, 0
            //   4c8b4c2450           | add                 dword ptr [eax], eax
            //   4c8b442458           | add                 byte ptr [eax], al
            //   488b542460           | inc                 ecx
            //   33c9                 | not                 eax

        $sequence_8 = { 4156 66440fbeca 0fbfd9 660fb6f9 50 480fb7f1 4d8bd4 }
            // n = 7, score = 100
            //   4156                 | test                ch, 0x3d
            //   66440fbeca           | xor                 al, al
            //   0fbfd9               | dec                 eax
            //   660fb6f9             | add                 esp, 0x20
            //   50                   | pop                 ebx
            //   480fb7f1             | ret                 
            //   4d8bd4               | dec                 eax

        $sequence_9 = { 0f8cc6010000 41b816000000 488d15993c0300 488bcb e8???????? 85c0 }
            // n = 6, score = 100
            //   0f8cc6010000         | sub                 eax, ebp
            //   41b816000000         | stc                 
            //   488d15993c0300       | inc                 ecx
            //   488bcb               | shr                 dl, 0x9b
            //   e8????????           |                     
            //   85c0                 | sub                 dl, 0xbc

    condition:
        7 of them and filesize < 19536896
}