rule win_xxmm_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.xxmm."
        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.xxmm"
        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 = { 8945e0 eb20 81fb54caaf91 7509 8b00 03c1 8945ec }
            // n = 7, score = 600
            //   8945e0               | mov                 dword ptr [ebp - 0x20], eax
            //   eb20                 | jmp                 0x22
            //   81fb54caaf91         | cmp                 ebx, 0x91afca54
            //   7509                 | jne                 0xb
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   03c1                 | add                 eax, ecx
            //   8945ec               | mov                 dword ptr [ebp - 0x14], eax

        $sequence_1 = { 740b 2bfb 8a11 88140f }
            // n = 4, score = 600
            //   740b                 | je                  0xd
            //   2bfb                 | sub                 edi, ebx
            //   8a11                 | mov                 dl, byte ptr [ecx]
            //   88140f               | mov                 byte ptr [edi + ecx], dl

        $sequence_2 = { 8b440e24 03f9 03c1 8945f8 c745f404000000 8b07 03c1 }
            // n = 7, score = 600
            //   8b440e24             | mov                 eax, dword ptr [esi + ecx + 0x24]
            //   03f9                 | add                 edi, ecx
            //   03c1                 | add                 eax, ecx
            //   8945f8               | mov                 dword ptr [ebp - 8], eax
            //   c745f404000000       | mov                 dword ptr [ebp - 0xc], 4
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   03c1                 | add                 eax, ecx

        $sequence_3 = { 8bd9 894c2420 741c 48 }
            // n = 4, score = 600
            //   8bd9                 | mov                 ebx, ecx
            //   894c2420             | mov                 dword ptr [esp + 0x20], ecx
            //   741c                 | je                  0x1e
            //   48                   | dec                 eax

        $sequence_4 = { 4f 81cf00ffffff 47 8d040f 0fb610 035510 81e2ff000080 }
            // n = 7, score = 600
            //   4f                   | dec                 edi
            //   81cf00ffffff         | or                  edi, 0xffffff00
            //   47                   | inc                 edi
            //   8d040f               | lea                 eax, [edi + ecx]
            //   0fb610               | movzx               edx, byte ptr [eax]
            //   035510               | add                 edx, dword ptr [ebp + 0x10]
            //   81e2ff000080         | and                 edx, 0x800000ff

        $sequence_5 = { 8b440878 8b7c0820 8b540824 03f9 03d1 8955f8 }
            // n = 6, score = 600
            //   8b440878             | mov                 eax, dword ptr [eax + ecx + 0x78]
            //   8b7c0820             | mov                 edi, dword ptr [eax + ecx + 0x20]
            //   8b540824             | mov                 edx, dword ptr [eax + ecx + 0x24]
            //   03f9                 | add                 edi, ecx
            //   03d1                 | add                 edx, ecx
            //   8955f8               | mov                 dword ptr [ebp - 8], edx

        $sequence_6 = { 8945e0 8b45f4 0fb700 668bf8 }
            // n = 4, score = 600
            //   8945e0               | mov                 dword ptr [ebp - 0x20], eax
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   0fb700               | movzx               eax, word ptr [eax]
            //   668bf8               | mov                 di, ax

        $sequence_7 = { 752b 33c9 ff15???????? b801000000 48 83c428 }
            // n = 6, score = 600
            //   752b                 | jne                 0x2d
            //   33c9                 | xor                 ecx, ecx
            //   ff15????????         |                     
            //   b801000000           | mov                 eax, 1
            //   48                   | dec                 eax
            //   83c428               | add                 esp, 0x28

        $sequence_8 = { 8b5dfc 83c728 837de800 75d7 8b9e80000000 }
            // n = 5, score = 600
            //   8b5dfc               | mov                 ebx, dword ptr [ebp - 4]
            //   83c728               | add                 edi, 0x28
            //   837de800             | cmp                 dword ptr [ebp - 0x18], 0
            //   75d7                 | jne                 0xffffffd9
            //   8b9e80000000         | mov                 ebx, dword ptr [esi + 0x80]

        $sequence_9 = { 03c1 81fb8e4e0eec 7509 8b00 03c1 }
            // n = 5, score = 600
            //   03c1                 | add                 eax, ecx
            //   81fb8e4e0eec         | cmp                 ebx, 0xec0e4e8e
            //   7509                 | jne                 0xb
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   03c1                 | add                 eax, ecx

    condition:
        7 of them and filesize < 540672
}

rule win_xxmm_w0 {
    meta:
        author = "Florian Roth"
        description = "Detects malware / hacktool sample from Bronze Butler incident"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.xxmm"
        malpedia_version = "20180301"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $x1 = "\\Release\\ReflectivLoader.pdb" ascii
        $x3 = "\\Projects\\xxmm2\\Release\\" ascii
        $x5 = "http://127.0.0.1/phptunnel.php" fullword ascii

        $s1 = "xxmm2.exe" fullword ascii
        $s2 = "\\AvUpdate.exe" fullword wide
        $s3 = "stdapi_fs_file_download" fullword ascii
        $s4 = "stdapi_syncshell_open" fullword ascii
        $s5 = "stdapi_execute_sleep" fullword ascii
        $s6 = "stdapi_syncshell_kill" fullword ascii
    condition:
        1 of ($x*) or
        4 of them
}