rule win_stealer_0x3401_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.stealer_0x3401."
        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.stealer_0x3401"
        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 = { a1???????? 33c4 89442420 53 56 57 68???????? }
            // n = 7, score = 100
            //   a1????????           |                     
            //   33c4                 | xor                 eax, esp
            //   89442420             | mov                 dword ptr [esp + 0x20], eax
            //   53                   | push                ebx
            //   56                   | push                esi
            //   57                   | push                edi
            //   68????????           |                     

        $sequence_1 = { 75f9 2bc2 50 57 8d4dd8 e8???????? 8d45d8 }
            // n = 7, score = 100
            //   75f9                 | jne                 0xfffffffb
            //   2bc2                 | sub                 eax, edx
            //   50                   | push                eax
            //   57                   | push                edi
            //   8d4dd8               | lea                 ecx, [ebp - 0x28]
            //   e8????????           |                     
            //   8d45d8               | lea                 eax, [ebp - 0x28]

        $sequence_2 = { ffd7 85c0 0f85ac010000 8985c8feffff 3906 }
            // n = 5, score = 100
            //   ffd7                 | call                edi
            //   85c0                 | test                eax, eax
            //   0f85ac010000         | jne                 0x1b2
            //   8985c8feffff         | mov                 dword ptr [ebp - 0x138], eax
            //   3906                 | cmp                 dword ptr [esi], eax

        $sequence_3 = { 8d8d60beffff 8d5102 90 668b01 }
            // n = 4, score = 100
            //   8d8d60beffff         | lea                 ecx, [ebp - 0x41a0]
            //   8d5102               | lea                 edx, [ecx + 2]
            //   90                   | nop                 
            //   668b01               | mov                 ax, word ptr [ecx]

        $sequence_4 = { e8???????? 83c404 894598 50 57 ffd6 }
            // n = 6, score = 100
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   894598               | mov                 dword ptr [ebp - 0x68], eax
            //   50                   | push                eax
            //   57                   | push                edi
            //   ffd6                 | call                esi

        $sequence_5 = { 7605 e8???????? 8bc8 51 e8???????? 83c404 6aff }
            // n = 7, score = 100
            //   7605                 | jbe                 7
            //   e8????????           |                     
            //   8bc8                 | mov                 ecx, eax
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   6aff                 | push                -1

        $sequence_6 = { 8d4d90 0f28d9 0f28d1 f20f591d???????? e8???????? 6aff }
            // n = 6, score = 100
            //   8d4d90               | lea                 ecx, [ebp - 0x70]
            //   0f28d9               | movaps              xmm3, xmm1
            //   0f28d1               | movaps              xmm2, xmm1
            //   f20f591d????????     |                     
            //   e8????????           |                     
            //   6aff                 | push                -1

        $sequence_7 = { 8b4710 c6040800 8d4601 3b4508 8b45f0 0f8315020000 0fb60c06 }
            // n = 7, score = 100
            //   8b4710               | mov                 eax, dword ptr [edi + 0x10]
            //   c6040800             | mov                 byte ptr [eax + ecx], 0
            //   8d4601               | lea                 eax, [esi + 1]
            //   3b4508               | cmp                 eax, dword ptr [ebp + 8]
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]
            //   0f8315020000         | jae                 0x21b
            //   0fb60c06             | movzx               ecx, byte ptr [esi + eax]

        $sequence_8 = { 8d90b4610210 5f 668b02 8d5202 668901 8d4902 83ef01 }
            // n = 7, score = 100
            //   8d90b4610210         | lea                 edx, [eax + 0x100261b4]
            //   5f                   | pop                 edi
            //   668b02               | mov                 ax, word ptr [edx]
            //   8d5202               | lea                 edx, [edx + 2]
            //   668901               | mov                 word ptr [ecx], ax
            //   8d4902               | lea                 ecx, [ecx + 2]
            //   83ef01               | sub                 edi, 1

        $sequence_9 = { 6aff 68???????? 64a100000000 50 b8a0820000 e8???????? a1???????? }
            // n = 7, score = 100
            //   6aff                 | push                -1
            //   68????????           |                     
            //   64a100000000         | mov                 eax, dword ptr fs:[0]
            //   50                   | push                eax
            //   b8a0820000           | mov                 eax, 0x82a0
            //   e8????????           |                     
            //   a1????????           |                     

    condition:
        7 of them and filesize < 357376
}