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 (20230715 | Detects win.dexbia.)
rule win_dexbia_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        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 = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { f3a5 b918000000 8d7c2425 f3ab 66ab aa }
            // n = 6, score = 200
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   b918000000           | mov                 ecx, 0x18
            //   8d7c2425             | lea                 edi, [esp + 0x25]
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   aa                   | stosb               byte ptr es:[edi], al

        $sequence_1 = { b910000000 85c0 7415 33c0 bf???????? 68???????? }
            // n = 6, score = 200
            //   b910000000           | mov                 ecx, 0x10
            //   85c0                 | test                eax, eax
            //   7415                 | je                  0x17
            //   33c0                 | xor                 eax, eax
            //   bf????????           |                     
            //   68????????           |                     

        $sequence_2 = { ffd7 55 ffd7 5f 5e 5d 33c0 }
            // n = 7, score = 200
            //   ffd7                 | call                edi
            //   55                   | push                ebp
            //   ffd7                 | call                edi
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   33c0                 | xor                 eax, eax

        $sequence_3 = { 8d4c2418 51 68???????? e8???????? 8d542420 }
            // n = 5, score = 200
            //   8d4c2418             | lea                 ecx, [esp + 0x18]
            //   51                   | push                ecx
            //   68????????           |                     
            //   e8????????           |                     
            //   8d542420             | lea                 edx, [esp + 0x20]

        $sequence_4 = { 7f0e 0fbec3 8a8054714000 83e00f eb02 }
            // n = 5, score = 200
            //   7f0e                 | jg                  0x10
            //   0fbec3               | movsx               eax, bl
            //   8a8054714000         | mov                 al, byte ptr [eax + 0x407154]
            //   83e00f               | and                 eax, 0xf
            //   eb02                 | jmp                 4

        $sequence_5 = { 68???????? e8???????? 83c438 33c0 5f 5e 5d }
            // n = 7, score = 200
            //   68????????           |                     
            //   e8????????           |                     
            //   83c438               | add                 esp, 0x38
            //   33c0                 | xor                 eax, eax
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp

        $sequence_6 = { 6a10 52 8b08 6aff }
            // n = 4, score = 200
            //   6a10                 | push                0x10
            //   52                   | push                edx
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   6aff                 | push                -1

        $sequence_7 = { 205a40 004c5a40 00705a 40 0023 d18a0688078a }
            // n = 6, score = 200
            //   205a40               | and                 byte ptr [edx + 0x40], bl
            //   004c5a40             | add                 byte ptr [edx + ebx*2 + 0x40], cl
            //   00705a               | add                 byte ptr [eax + 0x5a], dh
            //   40                   | inc                 eax
            //   0023                 | add                 byte ptr [ebx], ah
            //   d18a0688078a         | ror                 dword ptr [edx - 0x75f877fa], 1

        $sequence_8 = { f3ab 66ab aa 8b842418780000 8d4c240c }
            // n = 5, score = 200
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   aa                   | stosb               byte ptr es:[edi], al
            //   8b842418780000       | mov                 eax, dword ptr [esp + 0x7818]
            //   8d4c240c             | lea                 ecx, [esp + 0xc]

        $sequence_9 = { 66895c2418 66899c248c000000 f3ab 66ab b981000000 }
            // n = 5, score = 200
            //   66895c2418           | mov                 word ptr [esp + 0x18], bx
            //   66899c248c000000     | mov                 word ptr [esp + 0x8c], bx
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   66ab                 | stosw               word ptr es:[edi], ax
            //   b981000000           | mov                 ecx, 0x81

    condition:
        7 of them and filesize < 106496
}
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