SYMBOLCOMMON_NAMEaka. SYNONYMS
win.mmon (Back to overview)

MMON

aka: Kaptoxa

There is no description at this point.

References
2022-01-02ReversingFunilbaroni
@online{ilbaroni:20220102:mmon:51d45d7, author = {ilbaroni}, title = {{MMON (aka KAPTOXA)}}, date = {2022-01-02}, organization = {ReversingFun}, url = {http://reversing.fun/posts/2022/01/02/mmon.html}, language = {English}, urldate = {2022-01-05} } MMON (aka KAPTOXA)
MMON
Yara Rules
[TLP:WHITE] win_mmon_auto (20230715 | Detects win.mmon.)
rule win_mmon_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.mmon."
        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.mmon"
        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 = { 83feff 7e5b eb03 8b5508 0fbe1416 52 e8???????? }
            // n = 7, score = 100
            //   83feff               | cmp                 esi, -1
            //   7e5b                 | jle                 0x5d
            //   eb03                 | jmp                 5
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   0fbe1416             | movsx               edx, byte ptr [esi + edx]
            //   52                   | push                edx
            //   e8????????           |                     

        $sequence_1 = { 3975e4 7303 8d45d0 8b8d54ffffff 8b11 8910 }
            // n = 6, score = 100
            //   3975e4               | cmp                 dword ptr [ebp - 0x1c], esi
            //   7303                 | jae                 5
            //   8d45d0               | lea                 eax, [ebp - 0x30]
            //   8b8d54ffffff         | mov                 ecx, dword ptr [ebp - 0xac]
            //   8b11                 | mov                 edx, dword ptr [ecx]
            //   8910                 | mov                 dword ptr [eax], edx

        $sequence_2 = { 40 cd40 0064cd40 008ccd40008a46 0323 d188470383ee }
            // n = 6, score = 100
            //   40                   | inc                 eax
            //   cd40                 | int                 0x40
            //   0064cd40             | add                 byte ptr [ebp + ecx*8 + 0x40], ah
            //   008ccd40008a46       | add                 byte ptr [ebp + ecx*8 + 0x468a0040], cl
            //   0323                 | add                 esp, dword ptr [ebx]
            //   d188470383ee         | ror                 dword ptr [eax - 0x117cfcb9], 1

        $sequence_3 = { 899554ffffff 898548ffffff 8d642400 8a07 3c30 }
            // n = 5, score = 100
            //   899554ffffff         | mov                 dword ptr [ebp - 0xac], edx
            //   898548ffffff         | mov                 dword ptr [ebp - 0xb8], eax
            //   8d642400             | lea                 esp, [esp]
            //   8a07                 | mov                 al, byte ptr [edi]
            //   3c30                 | cmp                 al, 0x30

        $sequence_4 = { 50 ff15???????? ffd6 50 e8???????? 8b44241c }
            // n = 6, score = 100
            //   50                   | push                eax
            //   ff15????????         |                     
            //   ffd6                 | call                esi
            //   50                   | push                eax
            //   e8????????           |                     
            //   8b44241c             | mov                 eax, dword ptr [esp + 0x1c]

        $sequence_5 = { 8b17 68???????? 51 52 }
            // n = 4, score = 100
            //   8b17                 | mov                 edx, dword ptr [edi]
            //   68????????           |                     
            //   51                   | push                ecx
            //   52                   | push                edx

        $sequence_6 = { ebd2 8bc3 c1f805 8d3c85606a4200 8bf3 83e61f c1e606 }
            // n = 7, score = 100
            //   ebd2                 | jmp                 0xffffffd4
            //   8bc3                 | mov                 eax, ebx
            //   c1f805               | sar                 eax, 5
            //   8d3c85606a4200       | lea                 edi, [eax*4 + 0x426a60]
            //   8bf3                 | mov                 esi, ebx
            //   83e61f               | and                 esi, 0x1f
            //   c1e606               | shl                 esi, 6

        $sequence_7 = { c7854cffffff00000000 b801000000 018554ffffff 018548ffffff 03f8 3bbd50ffffff }
            // n = 6, score = 100
            //   c7854cffffff00000000     | mov    dword ptr [ebp - 0xb4], 0
            //   b801000000           | mov                 eax, 1
            //   018554ffffff         | add                 dword ptr [ebp - 0xac], eax
            //   018548ffffff         | add                 dword ptr [ebp - 0xb8], eax
            //   03f8                 | add                 edi, eax
            //   3bbd50ffffff         | cmp                 edi, dword ptr [ebp - 0xb0]

        $sequence_8 = { 8b0d???????? 85c9 7406 8b55ec }
            // n = 4, score = 100
            //   8b0d????????         |                     
            //   85c9                 | test                ecx, ecx
            //   7406                 | je                  8
            //   8b55ec               | mov                 edx, dword ptr [ebp - 0x14]

        $sequence_9 = { 6a00 8bf1 c745d000000000 ff15???????? 8bf8 33c0 4f }
            // n = 7, score = 100
            //   6a00                 | push                0
            //   8bf1                 | mov                 esi, ecx
            //   c745d000000000       | mov                 dword ptr [ebp - 0x30], 0
            //   ff15????????         |                     
            //   8bf8                 | mov                 edi, eax
            //   33c0                 | xor                 eax, eax
            //   4f                   | dec                 edi

    condition:
        7 of them and filesize < 356352
}
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