rule win_xxmm_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        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 = "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 = { ff15???????? ff7508 8bd8 57 53 895dfc e8???????? }
            // n = 7, score = 600
            //   ff15????????         |                     
            //   ff7508               | push                dword ptr [ebp + 8]
            //   8bd8                 | mov                 ebx, eax
            //   57                   | push                edi
            //   53                   | push                ebx
            //   895dfc               | mov                 dword ptr [ebp - 4], ebx
            //   e8????????           |                     

        $sequence_1 = { 83c704 66837df400 77b7 8b45f0 }
            // n = 4, score = 600
            //   83c704               | add                 edi, 4
            //   66837df400           | cmp                 word ptr [ebp - 0xc], 0
            //   77b7                 | ja                  0xffffffb9
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]

        $sequence_2 = { 8b4508 8908 5d c20800 55 8bec 83ec10 }
            // n = 7, score = 600
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8908                 | mov                 dword ptr [eax], ecx
            //   5d                   | pop                 ebp
            //   c20800               | ret                 8
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   83ec10               | sub                 esp, 0x10

        $sequence_3 = { 895d14 8a1b 895510 8a10 8818 }
            // n = 5, score = 600
            //   895d14               | mov                 dword ptr [ebp + 0x14], ebx
            //   8a1b                 | mov                 bl, byte ptr [ebx]
            //   895510               | mov                 dword ptr [ebp + 0x10], edx
            //   8a10                 | mov                 dl, byte ptr [eax]
            //   8818                 | mov                 byte ptr [eax], bl

        $sequence_4 = { 33c0 5f 5b c3 0fb7c7 }
            // n = 5, score = 600
            //   33c0                 | xor                 eax, eax
            //   5f                   | pop                 edi
            //   5b                   | pop                 ebx
            //   c3                   | ret                 
            //   0fb7c7               | movzx               eax, di

        $sequence_5 = { 03f9 03c1 8945f8 c745f404000000 8b07 03c1 }
            // n = 6, score = 600
            //   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_6 = { 750a 8b7dfc 23c3 013c08 eb1e }
            // n = 5, score = 600
            //   750a                 | jne                 0xc
            //   8b7dfc               | mov                 edi, dword ptr [ebp - 4]
            //   23c3                 | and                 eax, ebx
            //   013c08               | add                 dword ptr [eax + ecx], edi
            //   eb1e                 | jmp                 0x20

        $sequence_7 = { 895dfc b84d5a0000 663903 7517 8b433c }
            // n = 5, score = 600
            //   895dfc               | mov                 dword ptr [ebp - 4], ebx
            //   b84d5a0000           | mov                 eax, 0x5a4d
            //   663903               | cmp                 word ptr [ebx], ax
            //   7517                 | jne                 0x19
            //   8b433c               | mov                 eax, dword ptr [ebx + 0x3c]

        $sequence_8 = { 7414 394de0 740f 394dec 740a 394de8 7405 }
            // n = 7, score = 600
            //   7414                 | je                  0x16
            //   394de0               | cmp                 dword ptr [ebp - 0x20], ecx
            //   740f                 | je                  0x11
            //   394dec               | cmp                 dword ptr [ebp - 0x14], ecx
            //   740a                 | je                  0xc
            //   394de8               | cmp                 dword ptr [ebp - 0x18], ecx
            //   7405                 | je                  7

        $sequence_9 = { c1cb0d 03da 40 8a10 84d2 }
            // n = 5, score = 600
            //   c1cb0d               | ror                 ebx, 0xd
            //   03da                 | add                 ebx, edx
            //   40                   | inc                 eax
            //   8a10                 | mov                 dl, byte ptr [eax]
            //   84d2                 | test                dl, dl

    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
}