SYMBOLCOMMON_NAMEaka. SYNONYMS
win.aukill (Back to overview)

AuKill

aka: SophosKill
VTCollection    

According to Sophos, the AuKill tool abuses an outdated version of the driver used by version 16.32 of the Microsoft utility, Process Explorer, to disable EDR processes before deploying either a backdoor or ransomware on the target system.

References
2023-04-19SophosAndreas Klopsch
‘AuKill’ EDR killer malware abuses Process Explorer driver
AuKill
Yara Rules
[TLP:WHITE] win_aukill_auto (20251219 | Detects win.aukill.)
rule win_aukill_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-01-05"
        version = "1"
        description = "Detects win.aukill."
        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.aukill"
        malpedia_rule_date = "20260105"
        malpedia_hash = "19b79e7cab4eaf532122e5b45a77dd8f6bb5cc79"
        malpedia_version = "20251219"
        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 = { 33d2 b940040000 ff15???????? 488bd8 }
            // n = 4, score = 200
            //   33d2                 | lea                 ecx, [0xe247]
            //   b940040000           | dec                 ecx
            //   ff15????????         |                     
            //   488bd8               | mov                 edx, ecx

        $sequence_1 = { 488b442460 4c8d442430 488b4c2458 33d2 4889442434 }
            // n = 5, score = 200
            //   488b442460           | dec                 eax
            //   4c8d442430           | cmp                 dword ptr [eax + 0x138], edi
            //   488b4c2458           | dec                 eax
            //   33d2                 | lea                 edx, [0xdc44]
            //   4889442434           | dec                 eax

        $sequence_2 = { 48894c2430 ba04003583 894c2428 48894c2420 448d4920 48894c2450 488b0d???????? }
            // n = 7, score = 200
            //   48894c2430           | dec                 eax
            //   ba04003583           | lea                 ecx, [0x14990]
            //   894c2428             | inc                 ecx
            //   48894c2420           | and                 edx, 0x3f
            //   448d4920             | dec                 ecx
            //   48894c2450           | add                 ebp, eax
            //   488b0d????????       |                     

        $sequence_3 = { 771c 488b0b ff15???????? 0fb608 }
            // n = 4, score = 200
            //   771c                 | lea                 edx, [0x209a7]
            //   488b0b               | dec                 eax
            //   ff15????????         |                     
            //   0fb608               | lea                 ecx, [0x209b2]

        $sequence_4 = { 33c9 48895c2440 48894c2438 4c8d442440 48894c2430 ba04003583 }
            // n = 6, score = 200
            //   33c9                 | mov                 dword ptr [esp + 0x28], eax
            //   48895c2440           | dec                 eax
            //   48894c2438           | lea                 eax, [eax + 1]
            //   4c8d442440           | jne                 0x13ac
            //   48894c2430           | dec                 eax
            //   ba04003583           | mov                 ecx, dword ptr [esp + 0x50]

        $sequence_5 = { 488b442460 4c8d442430 488b4c2458 33d2 }
            // n = 4, score = 200
            //   488b442460           | cmp                 ecx, eax
            //   4c8d442430           | dec                 eax
            //   488b4c2458           | cmp                 ebx, eax
            //   33d2                 | jne                 0x68b

        $sequence_6 = { 48894c2420 448d4920 48894c2450 488b0d???????? }
            // n = 4, score = 200
            //   48894c2420           | lea                 eax, [0x2069f]
            //   448d4920             | inc                 ecx
            //   48894c2450           | mov                 edx, esp
            //   488b0d????????       |                     

        $sequence_7 = { 448d4920 48894c2450 488b0d???????? 48897c2458 4889442448 }
            // n = 5, score = 200
            //   448d4920             | lea                 edx, [0x2111f]
            //   48894c2450           | mov                 dword ptr [esp + 0x4c], 2
            //   488b0d????????       |                     
            //   48897c2458           | xor                 ecx, ecx
            //   4889442448           | mov                 dword ptr [esp + 0x40], ebx

        $sequence_8 = { ff15???????? 85c0 751d 488bcb ff15???????? ff15???????? }
            // n = 6, score = 200
            //   ff15????????         |                     
            //   85c0                 | jne                 0x7e4
            //   751d                 | dec                 eax
            //   488bcb               | mov                 eax, edi
            //   ff15????????         |                     
            //   ff15????????         |                     

        $sequence_9 = { 8905???????? c705????????02000000 48c705????????04000000 ff15???????? 488905???????? 4885c0 }
            // n = 6, score = 200
            //   8905????????         |                     
            //   c705????????02000000     |     
            //   48c705????????04000000     |     
            //   ff15????????         |                     
            //   488905????????       |                     
            //   4885c0               | inc                 eax

    condition:
        7 of them and filesize < 446464
}
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