SYMBOLCOMMON_NAMEaka. SYNONYMS
win.dexbia (Back to overview)

Dexbia

aka: CONIME

Actor(s): Tonto Team


There is no description at this point.

References
2020-10-03Trend MicroJaromír Hořejší, Daniel Lunghi, Cedric Pernet, Kazuki Fujisawa
@techreport{hoej:20201003:earth:688aaf8, author = {Jaromír Hořejší and Daniel Lunghi and Cedric Pernet and Kazuki Fujisawa}, title = {{Earth Akhlut: Exploring the Tools, Tactics, and Procedures of an Advanced Threat Actor Operating a Large Infrastructure}}, date = {2020-10-03}, institution = {Trend Micro}, url = {https://vblocalhost.com/uploads/VB2020-Lunghi-Horejsi.pdf}, language = {English}, urldate = {2020-10-06} } Earth Akhlut: Exploring the Tools, Tactics, and Procedures of an Advanced Threat Actor Operating a Large Infrastructure
Dexbia TypeHash
Yara Rules
[TLP:WHITE] win_dexbia_auto (20230125 | Detects win.dexbia.)
rule win_dexbia_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.dexbia."
        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.dexbia"
        malpedia_rule_date = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 5d 33c0 5b 81c408100000 c3 56 }
            // n = 6, score = 200
            //   5d                   | pop                 ebp
            //   33c0                 | xor                 eax, eax
            //   5b                   | pop                 ebx
            //   81c408100000         | add                 esp, 0x1008
            //   c3                   | ret                 
            //   56                   | push                esi

        $sequence_1 = { 56 8bf1 c1e603 3b9698844000 0f851c010000 a1???????? 83f801 }
            // n = 7, score = 200
            //   56                   | push                esi
            //   8bf1                 | mov                 esi, ecx
            //   c1e603               | shl                 esi, 3
            //   3b9698844000         | cmp                 edx, dword ptr [esi + 0x408498]
            //   0f851c010000         | jne                 0x122
            //   a1????????           |                     
            //   83f801               | cmp                 eax, 1

        $sequence_2 = { 8d4c2438 51 ff15???????? a1???????? b907000000 }
            // n = 5, score = 200
            //   8d4c2438             | lea                 ecx, [esp + 0x38]
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   a1????????           |                     
            //   b907000000           | mov                 ecx, 7

        $sequence_3 = { 8dbc24f9070000 c68424f807000000 f3ab 66ab 8d8c2488000000 }
            // n = 5, score = 200
            //   8dbc24f9070000       | lea                 edi, [esp + 0x7f9]
            //   c68424f807000000     | mov                 byte ptr [esp + 0x7f8], 0
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   8d8c2488000000       | lea                 ecx, [esp + 0x88]

        $sequence_4 = { 0fb6d2 f682a19f400004 740c ff01 85f6 7406 }
            // n = 6, score = 200
            //   0fb6d2               | movzx               edx, dl
            //   f682a19f400004       | test                byte ptr [edx + 0x409fa1], 4
            //   740c                 | je                  0xe
            //   ff01                 | inc                 dword ptr [ecx]
            //   85f6                 | test                esi, esi
            //   7406                 | je                  8

        $sequence_5 = { 33c0 8dbc249d120000 889c249c260000 f3ab }
            // n = 4, score = 200
            //   33c0                 | xor                 eax, eax
            //   8dbc249d120000       | lea                 edi, [esp + 0x129d]
            //   889c249c260000       | mov                 byte ptr [esp + 0x269c], bl
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax

        $sequence_6 = { ff15???????? 85c0 7437 8d542418 }
            // n = 4, score = 200
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7437                 | je                  0x39
            //   8d542418             | lea                 edx, [esp + 0x18]

        $sequence_7 = { 85f6 7453 68???????? 56 ff15???????? 85c0 }
            // n = 6, score = 200
            //   85f6                 | test                esi, esi
            //   7453                 | je                  0x55
            //   68????????           |                     
            //   56                   | push                esi
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax

        $sequence_8 = { 56 ff15???????? 85c0 7443 8b8c242c100000 8b942428100000 }
            // n = 6, score = 200
            //   56                   | push                esi
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7443                 | je                  0x45
            //   8b8c242c100000       | mov                 ecx, dword ptr [esp + 0x102c]
            //   8b942428100000       | mov                 edx, dword ptr [esp + 0x1028]

        $sequence_9 = { 6a00 6800004804 6a00 6a00 68???????? 52 }
            // n = 6, score = 200
            //   6a00                 | push                0
            //   6800004804           | push                0x4480000
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   68????????           |                     
            //   52                   | push                edx

    condition:
        7 of them and filesize < 106496
}
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