rule win_dadstache_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-12-06"
        version = "1"
        description = "Detects win.dadstache."
        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.dadstache"
        malpedia_rule_date = "20231130"
        malpedia_hash = "fc8a0e9f343f6d6ded9e7df1a64dac0cc68d7351"
        malpedia_version = "20230808"
        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 = { 8d442414 50 6a1f ff35???????? }
            // n = 4, score = 500
            //   8d442414             | lea                 eax, [esp + 0x14]
            //   50                   | push                eax
            //   6a1f                 | push                0x1f
            //   ff35????????         |                     

        $sequence_1 = { 8b470c 8bf9 31460c 0f1006 c7450c09000000 0f1145e8 }
            // n = 6, score = 500
            //   8b470c               | mov                 eax, dword ptr [edi + 0xc]
            //   8bf9                 | mov                 edi, ecx
            //   31460c               | xor                 dword ptr [esi + 0xc], eax
            //   0f1006               | movups              xmm0, xmmword ptr [esi]
            //   c7450c09000000       | mov                 dword ptr [ebp + 0xc], 9
            //   0f1145e8             | movups              xmmword ptr [ebp - 0x18], xmm0

        $sequence_2 = { 85c0 7550 8b0d???????? 8b35???????? 85c9 7403 }
            // n = 6, score = 500
            //   85c0                 | test                eax, eax
            //   7550                 | jne                 0x52
            //   8b0d????????         |                     
            //   8b35????????         |                     
            //   85c9                 | test                ecx, ecx
            //   7403                 | je                  5

        $sequence_3 = { 53 8d4d08 895d08 51 53 50 53 }
            // n = 7, score = 500
            //   53                   | push                ebx
            //   8d4d08               | lea                 ecx, [ebp + 8]
            //   895d08               | mov                 dword ptr [ebp + 8], ebx
            //   51                   | push                ecx
            //   53                   | push                ebx
            //   50                   | push                eax
            //   53                   | push                ebx

        $sequence_4 = { 837c242c10 8d442418 51 0f4344241c }
            // n = 4, score = 500
            //   837c242c10           | cmp                 dword ptr [esp + 0x2c], 0x10
            //   8d442418             | lea                 eax, [esp + 0x18]
            //   51                   | push                ecx
            //   0f4344241c           | cmovae              eax, dword ptr [esp + 0x1c]

        $sequence_5 = { 8d5201 8842ff 83e901 75f2 8bd3 c1ea04 }
            // n = 6, score = 500
            //   8d5201               | lea                 edx, [edx + 1]
            //   8842ff               | mov                 byte ptr [edx - 1], al
            //   83e901               | sub                 ecx, 1
            //   75f2                 | jne                 0xfffffff4
            //   8bd3                 | mov                 edx, ebx
            //   c1ea04               | shr                 edx, 4

        $sequence_6 = { 6aff 6a00 8d442438 c74424340f000000 50 }
            // n = 5, score = 500
            //   6aff                 | push                -1
            //   6a00                 | push                0
            //   8d442438             | lea                 eax, [esp + 0x38]
            //   c74424340f000000     | mov                 dword ptr [esp + 0x34], 0xf
            //   50                   | push                eax

        $sequence_7 = { 6a1f ff35???????? ff15???????? a1???????? }
            // n = 4, score = 500
            //   6a1f                 | push                0x1f
            //   ff35????????         |                     
            //   ff15????????         |                     
            //   a1????????           |                     

        $sequence_8 = { 741b 8b45f0 47 83c628 3bf8 }
            // n = 5, score = 200
            //   741b                 | je                  0x1d
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]
            //   47                   | inc                 edi
            //   83c628               | add                 esi, 0x28
            //   3bf8                 | cmp                 edi, eax

        $sequence_9 = { 7405 8b4718 8901 8b731c 57 }
            // n = 5, score = 200
            //   7405                 | je                  7
            //   8b4718               | mov                 eax, dword ptr [edi + 0x18]
            //   8901                 | mov                 dword ptr [ecx], eax
            //   8b731c               | mov                 esi, dword ptr [ebx + 0x1c]
            //   57                   | push                edi

        $sequence_10 = { 42 83c628 8955f0 3b55e4 0f8c66ffffff }
            // n = 5, score = 200
            //   42                   | inc                 edx
            //   83c628               | add                 esi, 0x28
            //   8955f0               | mov                 dword ptr [ebp - 0x10], edx
            //   3b55e4               | cmp                 edx, dword ptr [ebp - 0x1c]
            //   0f8c66ffffff         | jl                  0xffffff6c

        $sequence_11 = { 7325 8b7c240c 4a 03d7 8d4fff }
            // n = 5, score = 200
            //   7325                 | jae                 0x27
            //   8b7c240c             | mov                 edi, dword ptr [esp + 0xc]
            //   4a                   | dec                 edx
            //   03d7                 | add                 edx, edi
            //   8d4fff               | lea                 ecx, [edi - 1]

        $sequence_12 = { 8b4485b0 85d2 8b56f8 7405 0d00020000 8d5de4 53 }
            // n = 7, score = 200
            //   8b4485b0             | mov                 eax, dword ptr [ebp + eax*4 - 0x50]
            //   85d2                 | test                edx, edx
            //   8b56f8               | mov                 edx, dword ptr [esi - 8]
            //   7405                 | je                  7
            //   0d00020000           | or                  eax, 0x200
            //   8d5de4               | lea                 ebx, [ebp - 0x1c]
            //   53                   | push                ebx

        $sequence_13 = { e8???????? 85c0 741d 8bce e8???????? 8bce }
            // n = 6, score = 200
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   741d                 | je                  0x1f
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   8bce                 | mov                 ecx, esi

        $sequence_14 = { c3 8b4e04 8d4604 8945fc 8b06 }
            // n = 5, score = 200
            //   c3                   | ret                 
            //   8b4e04               | mov                 ecx, dword ptr [esi + 4]
            //   8d4604               | lea                 eax, [esi + 4]
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   8b06                 | mov                 eax, dword ptr [esi]

        $sequence_15 = { 84c9 740e 3aca 74ef 0fb6c2 0fb6c9 }
            // n = 6, score = 200
            //   84c9                 | test                cl, cl
            //   740e                 | je                  0x10
            //   3aca                 | cmp                 cl, dl
            //   74ef                 | je                  0xfffffff1
            //   0fb6c2               | movzx               eax, dl
            //   0fb6c9               | movzx               ecx, cl

    condition:
        7 of them and filesize < 580608
}

rule win_dadstache_w0 {
    meta:
        author =  "Elastic Security"
        description = "APT40 second stage implant"
        source = "https://www.elastic.co/blog/advanced-techniques-used-in-malaysian-focused-apt-campaign"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.dadstache"
        malpedia_version = "20200626"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $a = "/list_direction" fullword wide
        $b = "/post_document" fullword wide
        $c = "/postlogin" fullword wide
        $d = "Download Read Path Failed %s" fullword ascii
        $e = "Open Pipe Failed %s" fullword ascii
        $f = "Open Remote File %s Failed For: %s" fullword ascii
        $g = "Download Read Path Failed %s" fullword ascii
        $h = "\\cmd.exe" fullword wide
    condition:
        all of them
}