rule win_nocturnalstealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.nocturnalstealer."
        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.nocturnalstealer"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { ff32 81f624000000 bf00000000 bb00000000 89ee 81c720000000 81f700000080 }
            // n = 7, score = 100
            //   ff32                 | push                dword ptr [edx]
            //   81f624000000         | xor                 esi, 0x24
            //   bf00000000           | mov                 edi, 0
            //   bb00000000           | mov                 ebx, 0
            //   89ee                 | mov                 esi, ebp
            //   81c720000000         | add                 edi, 0x20
            //   81f700000080         | xor                 edi, 0x80000000

        $sequence_1 = { e9???????? 95 48 f7d0 3578a7d0a2 81eab2efe97c e9???????? }
            // n = 7, score = 100
            //   e9????????           |                     
            //   95                   | xchg                eax, ebp
            //   48                   | dec                 eax
            //   f7d0                 | not                 eax
            //   3578a7d0a2           | xor                 eax, 0xa2d0a778
            //   81eab2efe97c         | sub                 edx, 0x7ce9efb2
            //   e9????????           |                     

        $sequence_2 = { f7de e9???????? 83c004 870424 8b2424 c1e202 81c2394efb77 }
            // n = 7, score = 100
            //   f7de                 | neg                 esi
            //   e9????????           |                     
            //   83c004               | add                 eax, 4
            //   870424               | xchg                dword ptr [esp], eax
            //   8b2424               | mov                 esp, dword ptr [esp]
            //   c1e202               | shl                 edx, 2
            //   81c2394efb77         | add                 edx, 0x77fb4e39

        $sequence_3 = { ff95eaadbb18 89850826bc18 8d858b25bc18 51 c70424116f2e00 890c24 57 }
            // n = 7, score = 100
            //   ff95eaadbb18         | call                dword ptr [ebp + 0x18bbadea]
            //   89850826bc18         | mov                 dword ptr [ebp + 0x18bc2608], eax
            //   8d858b25bc18         | lea                 eax, [ebp + 0x18bc258b]
            //   51                   | push                ecx
            //   c70424116f2e00       | mov                 dword ptr [esp], 0x2e6f11
            //   890c24               | mov                 dword ptr [esp], ecx
            //   57                   | push                edi

        $sequence_4 = { ff3424 ff3424 5e 51 891c24 54 5b }
            // n = 7, score = 100
            //   ff3424               | push                dword ptr [esp]
            //   ff3424               | push                dword ptr [esp]
            //   5e                   | pop                 esi
            //   51                   | push                ecx
            //   891c24               | mov                 dword ptr [esp], ebx
            //   54                   | push                esp
            //   5b                   | pop                 ebx

        $sequence_5 = { ff3424 8b0424 81c404000000 53 89e3 56 be04000000 }
            // n = 7, score = 100
            //   ff3424               | push                dword ptr [esp]
            //   8b0424               | mov                 eax, dword ptr [esp]
            //   81c404000000         | add                 esp, 4
            //   53                   | push                ebx
            //   89e3                 | mov                 ebx, esp
            //   56                   | push                esi
            //   be04000000           | mov                 esi, 4

        $sequence_6 = { e9???????? 55 bd04000000 e9???????? 814424046f08fd7e 01542404 816c24046f08fd7e }
            // n = 7, score = 100
            //   e9????????           |                     
            //   55                   | push                ebp
            //   bd04000000           | mov                 ebp, 4
            //   e9????????           |                     
            //   814424046f08fd7e     | add                 dword ptr [esp + 4], 0x7efd086f
            //   01542404             | add                 dword ptr [esp + 4], edx
            //   816c24046f08fd7e     | sub                 dword ptr [esp + 4], 0x7efd086f

        $sequence_7 = { e9???????? 684d20d05f 890424 b89860dcbf e9???????? 55 bd225092fa }
            // n = 7, score = 100
            //   e9????????           |                     
            //   684d20d05f           | push                0x5fd0204d
            //   890424               | mov                 dword ptr [esp], eax
            //   b89860dcbf           | mov                 eax, 0xbfdc6098
            //   e9????????           |                     
            //   55                   | push                ebp
            //   bd225092fa           | mov                 ebp, 0xfa925022

        $sequence_8 = { e9???????? 58 50 68ea51fa66 892424 57 891424 }
            // n = 7, score = 100
            //   e9????????           |                     
            //   58                   | pop                 eax
            //   50                   | push                eax
            //   68ea51fa66           | push                0x66fa51ea
            //   892424               | mov                 dword ptr [esp], esp
            //   57                   | push                edi
            //   891424               | mov                 dword ptr [esp], edx

        $sequence_9 = { e9???????? 8b1c24 68c4bf062d 893424 e9???????? 57 51 }
            // n = 7, score = 100
            //   e9????????           |                     
            //   8b1c24               | mov                 ebx, dword ptr [esp]
            //   68c4bf062d           | push                0x2d06bfc4
            //   893424               | mov                 dword ptr [esp], esi
            //   e9????????           |                     
            //   57                   | push                edi
            //   51                   | push                ecx

    condition:
        7 of them and filesize < 10739712
}