rule win_misha_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2024-10-31"
        version = "1"
        description = "Detects win.misha."
        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.misha"
        malpedia_rule_date = "20241030"
        malpedia_hash = "26e26953c49c8efafbf72a38076855d578e0a2e4"
        malpedia_version = "20241030"
        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 = { e8???????? ff7508 8d45e8 50 e8???????? 83c414 eb02 }
            // n = 7, score = 300
            //   e8????????           |                     
            //   ff7508               | push                dword ptr [ebp + 8]
            //   8d45e8               | lea                 eax, [ebp - 0x18]
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c414               | add                 esp, 0x14
            //   eb02                 | jmp                 4

        $sequence_1 = { 8b45b8 8945c0 8b45b8 8945c8 c645df01 eb04 c645df01 }
            // n = 7, score = 300
            //   8b45b8               | mov                 eax, dword ptr [ebp - 0x48]
            //   8945c0               | mov                 dword ptr [ebp - 0x40], eax
            //   8b45b8               | mov                 eax, dword ptr [ebp - 0x48]
            //   8945c8               | mov                 dword ptr [ebp - 0x38], eax
            //   c645df01             | mov                 byte ptr [ebp - 0x21], 1
            //   eb04                 | jmp                 6
            //   c645df01             | mov                 byte ptr [ebp - 0x21], 1

        $sequence_2 = { eb04 8b542410 0fb64c240c 8bc1 4a 48 7422 }
            // n = 7, score = 300
            //   eb04                 | jmp                 6
            //   8b542410             | mov                 edx, dword ptr [esp + 0x10]
            //   0fb64c240c           | movzx               ecx, byte ptr [esp + 0xc]
            //   8bc1                 | mov                 eax, ecx
            //   4a                   | dec                 edx
            //   48                   | dec                 eax
            //   7422                 | je                  0x24

        $sequence_3 = { a5 a5 8b450c c780f800000004000000 8b450c c780f400000001000000 }
            // n = 6, score = 300
            //   a5                   | movsd               dword ptr es:[edi], dword ptr [esi]
            //   a5                   | movsd               dword ptr es:[edi], dword ptr [esi]
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]
            //   c780f800000004000000     | mov    dword ptr [eax + 0xf8], 4
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]
            //   c780f400000001000000     | mov    dword ptr [eax + 0xf4], 1

        $sequence_4 = { c3 55 8bec 81ec10020000 ff750c }
            // n = 5, score = 300
            //   c3                   | ret                 
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   81ec10020000         | sub                 esp, 0x210
            //   ff750c               | push                dword ptr [ebp + 0xc]

        $sequence_5 = { eb43 837d1400 7421 ff7518 ff7514 ff7510 }
            // n = 6, score = 300
            //   eb43                 | jmp                 0x45
            //   837d1400             | cmp                 dword ptr [ebp + 0x14], 0
            //   7421                 | je                  0x23
            //   ff7518               | push                dword ptr [ebp + 0x18]
            //   ff7514               | push                dword ptr [ebp + 0x14]
            //   ff7510               | push                dword ptr [ebp + 0x10]

        $sequence_6 = { 397d0c 7456 57 57 ff750c ff7508 }
            // n = 6, score = 300
            //   397d0c               | cmp                 dword ptr [ebp + 0xc], edi
            //   7456                 | je                  0x58
            //   57                   | push                edi
            //   57                   | push                edi
            //   ff750c               | push                dword ptr [ebp + 0xc]
            //   ff7508               | push                dword ptr [ebp + 8]

        $sequence_7 = { 2b4508 f7d8 48 e9???????? 837d1800 7419 }
            // n = 6, score = 300
            //   2b4508               | sub                 eax, dword ptr [ebp + 8]
            //   f7d8                 | neg                 eax
            //   48                   | dec                 eax
            //   e9????????           |                     
            //   837d1800             | cmp                 dword ptr [ebp + 0x18], 0
            //   7419                 | je                  0x1b

        $sequence_8 = { c78550feffff18181818 c78554feffff18181818 c78558feffff18181819 c7855cfeffff19191919 c78560feffff19191919 c78564feffff19191919 c78568feffff19191919 }
            // n = 7, score = 300
            //   c78550feffff18181818     | mov    dword ptr [ebp - 0x1b0], 0x18181818
            //   c78554feffff18181818     | mov    dword ptr [ebp - 0x1ac], 0x18181818
            //   c78558feffff18181819     | mov    dword ptr [ebp - 0x1a8], 0x19181818
            //   c7855cfeffff19191919     | mov    dword ptr [ebp - 0x1a4], 0x19191919
            //   c78560feffff19191919     | mov    dword ptr [ebp - 0x1a0], 0x19191919
            //   c78564feffff19191919     | mov    dword ptr [ebp - 0x19c], 0x19191919
            //   c78568feffff19191919     | mov    dword ptr [ebp - 0x198], 0x19191919

        $sequence_9 = { ff75dc 6a08 59 e8???????? 83c420 0fb6c0 85c0 }
            // n = 7, score = 300
            //   ff75dc               | push                dword ptr [ebp - 0x24]
            //   6a08                 | push                8
            //   59                   | pop                 ecx
            //   e8????????           |                     
            //   83c420               | add                 esp, 0x20
            //   0fb6c0               | movzx               eax, al
            //   85c0                 | test                eax, eax

    condition:
        7 of them and filesize < 710656
}

rule win_misha_w0 {

    meta:
        author = "Daniel Plohmann"
        description = "Detect the unpacked payload for win.misha."
        date = "20211109"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.misha"
        malpedia_rule_date = "20211009"
        malpedia_hash = ""
        malpedia_version = "20211009"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    strings:
        /*  @0x4252d7 - creating a heap buffer for the config
            8D 44 24 0C                   lea     eax, [esp+10h+var_4]
            68 CE 11 01 00                push    111CEh
            50                            push    eax
            BF 40 9F 01 00                mov     edi, 19F40h
            B9 58 D8 42 00                mov     ecx, offset inner_buffer
            8B C6                         mov     eax, esi
            89 7C 24 14                   mov     [esp+18h+var_4], edi
            E8 1C D4 FF FF                call    sub_422712
            59                            pop     ecx
            59                            pop     ecx
            85 C0                         test    eax, eax
            0F 85 A1 00 00 00             jnz     loc_4253A1
        */
        $config_heap_0 = {8D4424?? 68???????? 50 BF???????? B9???????? 8BC689?????? E8???????? 59 59 85C0 0F }

        /*  @0x425300 - creating a heap buffer for some x64 code
            8D 44 24 0C                   lea     eax, [esp+10h+var_4]
            68 91 F3 00 00                push    0F391h
            50                            push    eax
            8D 86 40 9F 01 00             lea     eax, [esi+19F40h]
            B9 28 EA 43 00                mov     ecx, offset inner_buffer_2
            C7 44 24 14 80 03 02 00       mov     [esp+18h+var_4], 20380h
            E8 F0 D3 FF FF                call    sub_422712
            59                            pop     ecx
            59                            pop     ecx
            85 C0                         test    eax, eax
            75 79                         jnz     short loc_4253A1
        */
        $config_heap_1 = { 8D4424?? 68???????? 50 8D86???????? B9???????? C74424?????????? E8???????? 59 59 85C0 75 }

        /*  @0x408549 - string decryption
            8B 45 F8                      mov     eax, [ebp+var_8]
            33 D2                         xor     edx, edx
            F7 75 14                      div     [ebp+dwKeyLen]
            8B 45 10                      mov     eax, [ebp+szKey]
            0F B6 0C 10                   movzx   ecx, byte ptr [eax+edx]
            8B 45 F8                      mov     eax, [ebp+var_8]
            33 D2                         xor     edx, edx
            BE 00 01 00 00                mov     esi, 100h
            F7 F6                         div     esi
            33 CA                         xor     ecx, edx
            8B 45 FC                      mov     eax, [ebp+var_4]
            03 45 F8                      add     eax, [ebp+var_8]
            0F B6 00                      movzx   eax, byte ptr [eax]
            33 C1                         xor     eax, ecx
            8B 4D FC                      mov     ecx, [ebp+var_4]
            03 4D F8                      add     ecx, [ebp+var_8]
            88 01                         mov     [ecx], al
            EB BF                         jmp     short loc_40853A
        */
        $string_decrypt = { 8B45?? 33D2 F7???? 8B45?? 0FB6???? 8B45?? 33D2 BE00010000 F7F6 33CA 8B45?? 0345?? 0FB6?? 33C1 8B4D?? 034D?? 8801 EB }
        
    condition:
        any of them
}