rule win_dadstache_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        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 = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 6a01 8d4301 50 ff35???????? ffd7 }
            // n = 5, score = 500
            //   6a01                 | push                1
            //   8d4301               | lea                 eax, [ebx + 1]
            //   50                   | push                eax
            //   ff35????????         |                     
            //   ffd7                 | call                edi

        $sequence_1 = { 8bec 51 6a00 6a00 8d45fc c745fc00000000 50 }
            // n = 7, score = 500
            //   8bec                 | mov                 ebp, esp
            //   51                   | push                ecx
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   8d45fc               | lea                 eax, [ebp - 4]
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0
            //   50                   | push                eax

        $sequence_2 = { 2bf2 90 8a0416 8d5201 }
            // n = 4, score = 500
            //   2bf2                 | sub                 esi, edx
            //   90                   | nop                 
            //   8a0416               | mov                 al, byte ptr [esi + edx]
            //   8d5201               | lea                 edx, [edx + 1]

        $sequence_3 = { 8d5302 46 ebd7 6a64 ffb31c020000 }
            // n = 5, score = 500
            //   8d5302               | lea                 edx, [ebx + 2]
            //   46                   | inc                 esi
            //   ebd7                 | jmp                 0xffffffd9
            //   6a64                 | push                0x64
            //   ffb31c020000         | push                dword ptr [ebx + 0x21c]

        $sequence_4 = { a1???????? 43 b904000000 83fb03 0f82dffdffff e9???????? 8d44244c }
            // n = 7, score = 500
            //   a1????????           |                     
            //   43                   | inc                 ebx
            //   b904000000           | mov                 ecx, 4
            //   83fb03               | cmp                 ebx, 3
            //   0f82dffdffff         | jb                  0xfffffde5
            //   e9????????           |                     
            //   8d44244c             | lea                 eax, [esp + 0x4c]

        $sequence_5 = { 50 ff15???????? 39b314020000 745b ffb310020000 }
            // n = 5, score = 500
            //   50                   | push                eax
            //   ff15????????         |                     
            //   39b314020000         | cmp                 dword ptr [ebx + 0x214], esi
            //   745b                 | je                  0x5d
            //   ffb310020000         | push                dword ptr [ebx + 0x210]

        $sequence_6 = { 83ec0c 8b4d08 53 83c102 c745f804000000 56 }
            // n = 6, score = 500
            //   83ec0c               | sub                 esp, 0xc
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   53                   | push                ebx
            //   83c102               | add                 ecx, 2
            //   c745f804000000       | mov                 dword ptr [ebp - 8], 4
            //   56                   | push                esi

        $sequence_7 = { 50 8d8c240c020000 e8???????? 8b4c242c 8bf0 83f910 }
            // n = 6, score = 500
            //   50                   | push                eax
            //   8d8c240c020000       | lea                 ecx, [esp + 0x20c]
            //   e8????????           |                     
            //   8b4c242c             | mov                 ecx, dword ptr [esp + 0x2c]
            //   8bf0                 | mov                 esi, eax
            //   83f910               | cmp                 ecx, 0x10

        $sequence_8 = { c745f4476c6f62 0f44d8 c745f8616c4672 8d45e8 66c745fc6565 50 }
            // n = 6, score = 200
            //   c745f4476c6f62       | mov                 dword ptr [ebp - 0xc], 0x626f6c47
            //   0f44d8               | cmove               ebx, eax
            //   c745f8616c4672       | mov                 dword ptr [ebp - 8], 0x72466c61
            //   8d45e8               | lea                 eax, [ebp - 0x18]
            //   66c745fc6565         | mov                 word ptr [ebp - 4], 0x6565
            //   50                   | push                eax

        $sequence_9 = { 56 57 85c0 0f8404020000 8b780c }
            // n = 5, score = 200
            //   56                   | push                esi
            //   57                   | push                edi
            //   85c0                 | test                eax, eax
            //   0f8404020000         | je                  0x20a
            //   8b780c               | mov                 edi, dword ptr [eax + 0xc]

        $sequence_10 = { 03c1 50 53 ff55f8 8b4dfc }
            // n = 5, score = 200
            //   03c1                 | add                 eax, ecx
            //   50                   | push                eax
            //   53                   | push                ebx
            //   ff55f8               | call                dword ptr [ebp - 8]
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]

        $sequence_11 = { 894608 8bce e8???????? 8bce 85c0 74d7 }
            // n = 6, score = 200
            //   894608               | mov                 dword ptr [esi + 8], eax
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   8bce                 | mov                 ecx, esi
            //   85c0                 | test                eax, eax
            //   74d7                 | je                  0xffffffd9

        $sequence_12 = { 57 6a1c 6a40 ffd0 }
            // n = 4, score = 200
            //   57                   | push                edi
            //   6a1c                 | push                0x1c
            //   6a40                 | push                0x40
            //   ffd0                 | call                eax

        $sequence_13 = { 8d5580 e8???????? 85c0 740e 8b36 3bf7 75eb }
            // n = 7, score = 200
            //   8d5580               | lea                 edx, [ebp - 0x80]
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   740e                 | je                  0x10
            //   8b36                 | mov                 esi, dword ptr [esi]
            //   3bf7                 | cmp                 esi, edi
            //   75eb                 | jne                 0xffffffed

        $sequence_14 = { 8b7c240c 85ff 7417 2bd6 0f1f8000000000 }
            // n = 5, score = 200
            //   8b7c240c             | mov                 edi, dword ptr [esp + 0xc]
            //   85ff                 | test                edi, edi
            //   7417                 | je                  0x19
            //   2bd6                 | sub                 edx, esi
            //   0f1f8000000000       | nop                 dword ptr [eax]

        $sequence_15 = { 51 ff55f4 8bf8 85ff 0f844fffffff ff75ec 8b45dc }
            // n = 7, score = 200
            //   51                   | push                ecx
            //   ff55f4               | call                dword ptr [ebp - 0xc]
            //   8bf8                 | mov                 edi, eax
            //   85ff                 | test                edi, edi
            //   0f844fffffff         | je                  0xffffff55
            //   ff75ec               | push                dword ptr [ebp - 0x14]
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]

    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
}