SYMBOLCOMMON_NAMEaka. SYNONYMS
win.nocturnalstealer (Back to overview)

Nocturnal Stealer


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References
2018-05-30ProofpointProofpoint Staff
@online{staff:20180530:thief:f62b0ed, author = {Proofpoint Staff}, title = {{Thief in the night: New Nocturnal Stealer grabs data on the cheap}}, date = {2018-05-30}, organization = {Proofpoint}, url = {https://www.proofpoint.com/us/threat-insight/post/thief-night-new-nocturnal-stealer-grabs-data-cheap}, language = {English}, urldate = {2019-12-20} } Thief in the night: New Nocturnal Stealer grabs data on the cheap
Nocturnal Stealer
Yara Rules
[TLP:WHITE] win_nocturnalstealer_auto (20221125 | Detects win.nocturnalstealer.)
rule win_nocturnalstealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-11-21"
        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 = "20221118"
        malpedia_hash = "e0702e2e6d1d00da65c8a29a4ebacd0a4c59e1af"
        malpedia_version = "20221125"
        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 = { e9???????? 890c24 e9???????? 83c404 ff3424 59 e9???????? }
            // n = 7, score = 100
            //   e9????????           |                     
            //   890c24               | mov                 dword ptr [esp], ecx
            //   e9????????           |                     
            //   83c404               | add                 esp, 4
            //   ff3424               | push                dword ptr [esp]
            //   59                   | pop                 ecx
            //   e9????????           |                     

        $sequence_1 = { e9???????? 81c404000000 83ec04 e9???????? 81ca3ac9fd7f 50 b805340280 }
            // n = 7, score = 100
            //   e9????????           |                     
            //   81c404000000         | add                 esp, 4
            //   83ec04               | sub                 esp, 4
            //   e9????????           |                     
            //   81ca3ac9fd7f         | or                  edx, 0x7ffdc93a
            //   50                   | push                eax
            //   b805340280           | mov                 eax, 0x80023405

        $sequence_2 = { f682e0a84b0001 740e 0fb64601 46 f680e0a84b0001 75f2 33c0 }
            // n = 7, score = 100
            //   f682e0a84b0001       | test                byte ptr [edx + 0x4ba8e0], 1
            //   740e                 | je                  0x10
            //   0fb64601             | movzx               eax, byte ptr [esi + 1]
            //   46                   | inc                 esi
            //   f680e0a84b0001       | test                byte ptr [eax + 0x4ba8e0], 1
            //   75f2                 | jne                 0xfffffff4
            //   33c0                 | xor                 eax, eax

        $sequence_3 = { c7852d07a41800000000 83780406 0f820a000000 c7856b38a41801000000 83bd0105a41800 0f8524000000 83bd6b38a41800 }
            // n = 7, score = 100
            //   c7852d07a41800000000     | mov    dword ptr [ebp + 0x18a4072d], 0
            //   83780406             | cmp                 dword ptr [eax + 4], 6
            //   0f820a000000         | jb                  0x10
            //   c7856b38a41801000000     | mov    dword ptr [ebp + 0x18a4386b], 1
            //   83bd0105a41800       | cmp                 dword ptr [ebp + 0x18a40501], 0
            //   0f8524000000         | jne                 0x2a
            //   83bd6b38a41800       | cmp                 dword ptr [ebp + 0x18a4386b], 0

        $sequence_4 = { f7d7 81ef48e28aa8 29f9 5f 53 bba8a0fb47 21d9 }
            // n = 7, score = 100
            //   f7d7                 | not                 edi
            //   81ef48e28aa8         | sub                 edi, 0xa88ae248
            //   29f9                 | sub                 ecx, edi
            //   5f                   | pop                 edi
            //   53                   | push                ebx
            //   bba8a0fb47           | mov                 ebx, 0x47fba0a8
            //   21d9                 | and                 ecx, ebx

        $sequence_5 = { e9???????? 21f1 5e 81c101000000 c1e101 e9???????? 89fa }
            // n = 7, score = 100
            //   e9????????           |                     
            //   21f1                 | and                 ecx, esi
            //   5e                   | pop                 esi
            //   81c101000000         | add                 ecx, 1
            //   c1e101               | shl                 ecx, 1
            //   e9????????           |                     
            //   89fa                 | mov                 edx, edi

        $sequence_6 = { c9 b9229020c1 2293b37453ba a6 cc f9 219ea8acbc67 }
            // n = 7, score = 100
            //   c9                   | leave               
            //   b9229020c1           | mov                 ecx, 0xc1209022
            //   2293b37453ba         | and                 dl, byte ptr [ebx - 0x45ac8b4d]
            //   a6                   | cmpsb               byte ptr [esi], byte ptr es:[edi]
            //   cc                   | int3                
            //   f9                   | stc                 
            //   219ea8acbc67         | and                 dword ptr [esi + 0x67bcaca8], ebx

        $sequence_7 = { f7d8 2db5d6ff4a 40 2dab7404dd 01c3 58 83c304 }
            // n = 7, score = 100
            //   f7d8                 | neg                 eax
            //   2db5d6ff4a           | sub                 eax, 0x4affd6b5
            //   40                   | inc                 eax
            //   2dab7404dd           | sub                 eax, 0xdd0474ab
            //   01c3                 | add                 ebx, eax
            //   58                   | pop                 eax
            //   83c304               | add                 ebx, 4

        $sequence_8 = { e9???????? 891424 e9???????? c70424abf44507 e9???????? 5a 81c404000000 }
            // n = 7, score = 100
            //   e9????????           |                     
            //   891424               | mov                 dword ptr [esp], edx
            //   e9????????           |                     
            //   c70424abf44507       | mov                 dword ptr [esp], 0x745f4ab
            //   e9????????           |                     
            //   5a                   | pop                 edx
            //   81c404000000         | add                 esp, 4

        $sequence_9 = { ff3424 8b1c24 83c404 83ec04 890c24 89e1 56 }
            // n = 7, score = 100
            //   ff3424               | push                dword ptr [esp]
            //   8b1c24               | mov                 ebx, dword ptr [esp]
            //   83c404               | add                 esp, 4
            //   83ec04               | sub                 esp, 4
            //   890c24               | mov                 dword ptr [esp], ecx
            //   89e1                 | mov                 ecx, esp
            //   56                   | push                esi

    condition:
        7 of them and filesize < 10739712
}
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