SYMBOLCOMMON_NAMEaka. SYNONYMS
win.enigma_loader (Back to overview)

Enigma Loader

VTCollection    

According to Trend Micro, this is a downloader, dedicated to stage execution of a second stage malware called Enigma Stealer.

References
2023-02-09 ⋅ Trend Micro ⋅ Aliakbar Zahravi, Peter Girnus
Enigma Stealer Targets Cryptocurrency Industry with Fake Jobs
Enigma Loader
Yara Rules
[TLP:WHITE] win_enigma_loader_auto (20260917 | Detects win.enigma_loader.)
rule win_enigma_loader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.enigma_loader."
        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.enigma_loader"
        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 = { 488d8a50000000 e9???????? 488d8ae0000000 e9???????? 488d8a30000000 e9???????? 488d8a60010000 }
            // n = 7, score = 100
            //   488d8a50000000       | mov                 ebx, ecx
            //   e9????????           |                     
            //   488d8ae0000000       | mov                 edx, 0x4cf45399
            //   e9????????           |                     
            //   488d8a30000000       | mov                 ecx, 0x10
            //   e9????????           |                     
            //   488d8a60010000       | dec                 esp

        $sequence_1 = { 4c8d4c2450 4c8d85c0020000 488d95c8020000 ff5010 84c0 0f84f7000000 498b4e10 }
            // n = 7, score = 100
            //   4c8d4c2450           | inc                 edx
            //   4c8d85c0020000       | dec                 eax
            //   488d95c8020000       | lea                 ecx, [ebp - 0x40]
            //   ff5010               | nop                 
            //   84c0                 | dec                 esp
            //   0f84f7000000         | mov                 eax, eax
            //   498b4e10             | dec                 eax

        $sequence_2 = { e9???????? 41b10d e9???????? 488b4f10 483b4f18 731f 488d4101 }
            // n = 7, score = 100
            //   e9????????           |                     
            //   41b10d               | mov                 ecx, edx
            //   e9????????           |                     
            //   488b4f10             | mov                 esi, eax
            //   483b4f18             | jmp                 0x1ca6
            //   731f                 | dec                 eax
            //   488d4101             | mov                 ecx, edx

        $sequence_3 = { 8d040e 488d8dc4060000 8985c0060000 e8???????? 488d0dfe6ffeff 48c1e602 0fb784b9a0b10200 }
            // n = 7, score = 100
            //   8d040e               | mov                 ecx, ebx
            //   488d8dc4060000       | cmp                 eax, esi
            //   8985c0060000         | je                  0x80
            //   e8????????           |                     
            //   488d0dfe6ffeff       | test                eax, eax
            //   48c1e602             | je                  0x1f
            //   0fb784b9a0b10200     | cmp                 ecx, 0xd

        $sequence_4 = { 488985a8010000 48899db0010000 498bd5 488bcb e8???????? 4889bdb0010000 488b4e20 }
            // n = 7, score = 100
            //   488985a8010000       | dec                 eax
            //   48899db0010000       | test                ecx, ecx
            //   498bd5               | je                  0x44
            //   488bcb               | dec                 eax
            //   e8????????           |                     
            //   4889bdb0010000       | lea                 eax, [0xa464]
            //   488b4e20             | dec                 eax

        $sequence_5 = { 4156 4157 4883ec30 4c8bf2 4c8bf9 b920000000 e8???????? }
            // n = 7, score = 100
            //   4156                 | dec                 ecx
            //   4157                 | sub                 eax, dword ptr [esi + 8]
            //   4883ec30             | dec                 eax
            //   4c8bf2               | sar                 eax, 3
            //   4c8bf9               | inc                 eax
            //   b920000000           | mov                 byte ptr [ebp + 0x2c0], dh
            //   e8????????           |                     

        $sequence_6 = { 4881ec90010000 4533f6 4d8be0 4c8bfa 4489b5e8000000 488bf1 4489742450 }
            // n = 7, score = 100
            //   4881ec90010000       | test                esi, esi
            //   4533f6               | inc                 ecx
            //   4d8be0               | lea                 ecx, [ecx + 2]
            //   4c8bfa               | sub                 eax, edx
            //   4489b5e8000000       | sar                 eax, 1
            //   488bf1               | inc                 ecx
            //   4489742450           | add                 eax, edx

        $sequence_7 = { 4c8965b0 40887598 488b55d8 493bd5 0f8247040000 48ffc2 488b4dc0 }
            // n = 7, score = 100
            //   4c8965b0             | nop                 
            //   40887598             | inc                 ecx
            //   488b55d8             | movups              xmm0, xmmword ptr [edi + 0x68]
            //   493bd5               | movups              xmmword ptr [ebp - 0x20], xmm0
            //   0f8247040000         | inc                 ecx
            //   48ffc2               | movups              xmm1, xmmword ptr [edi + 0x78]
            //   488b4dc0             | dec                 eax

        $sequence_8 = { 4c3bf5 7705 4533ff eb0b 4d8bfe 4c2bfd }
            // n = 6, score = 100
            //   4c3bf5               | sub                 ecx, 0x11
            //   7705                 | je                  0x226c
            //   4533ff               | sub                 ecx, 1
            //   eb0b                 | je                  0x220e
            //   4d8bfe               | dec                 eax
            //   4c2bfd               | lea                 edx, [esp + 0x20]

        $sequence_9 = { 33db 48891e 4d8bc6 48896e10 498bd4 48897e18 488bcb }
            // n = 7, score = 100
            //   33db                 | shr                 edx, 4
            //   48891e               | movsx               eax, dl
            //   4d8bc6               | imul                ecx, eax, 0x34
            //   48896e10             | inc                 ecx
            //   498bd4               | mov                 al, al
            //   48897e18             | movups              xmmword ptr [ebp - 0x70], xmm1
            //   488bcb               | dec                 esp

    condition:
        7 of them and filesize < 798720
}
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