rule win_dadstache_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-04-08"
        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 = "20220405"
        malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a"
        malpedia_version = "20220411"
        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 = { 5d c3 8b15???????? 8b35???????? a1???????? }
            // n = 5, score = 500
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   8b15????????         |                     
            //   8b35????????         |                     
            //   a1????????           |                     

        $sequence_1 = { 85c0 741f 6a00 8d442418 }
            // n = 4, score = 500
            //   85c0                 | test                eax, eax
            //   741f                 | je                  0x21
            //   6a00                 | push                0
            //   8d442418             | lea                 eax, dword ptr [esp + 0x18]

        $sequence_2 = { 68c8000000 ff15???????? 3bf7 0f826affffff eb0c ff35???????? ff15???????? }
            // n = 7, score = 500
            //   68c8000000           | push                0xc8
            //   ff15????????         |                     
            //   3bf7                 | cmp                 esi, edi
            //   0f826affffff         | jb                  0xffffff70
            //   eb0c                 | jmp                 0xe
            //   ff35????????         |                     
            //   ff15????????         |                     

        $sequence_3 = { ebd7 6a64 ffb31c020000 ff15???????? 85c0 0f8519010000 }
            // n = 6, score = 500
            //   ebd7                 | jmp                 0xffffffd9
            //   6a64                 | push                0x64
            //   ffb31c020000         | push                dword ptr [ebx + 0x21c]
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f8519010000         | jne                 0x11f

        $sequence_4 = { 8bec 51 6a00 6a00 8d45fc c745fc00000000 }
            // n = 6, score = 500
            //   8bec                 | mov                 ebp, esp
            //   51                   | push                ecx
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   8d45fc               | lea                 eax, dword ptr [ebp - 4]
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0

        $sequence_5 = { c705????????00000000 8be5 5d c3 85c0 }
            // n = 5, score = 500
            //   c705????????00000000     |     
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   85c0                 | test                eax, eax

        $sequence_6 = { 8bec 83ec0c 8b4d08 53 83c102 }
            // n = 5, score = 500
            //   8bec                 | mov                 ebp, esp
            //   83ec0c               | sub                 esp, 0xc
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   53                   | push                ebx
            //   83c102               | add                 ecx, 2

        $sequence_7 = { 0f4344240c 8d4c2424 50 e8???????? ff7520 }
            // n = 5, score = 500
            //   0f4344240c           | cmovae              eax, dword ptr [esp + 0xc]
            //   8d4c2424             | lea                 ecx, dword ptr [esp + 0x24]
            //   50                   | push                eax
            //   e8????????           |                     
            //   ff7520               | push                dword ptr [ebp + 0x20]

        $sequence_8 = { 0f2965c0 3bce 0f8cfcfeffff 660f383ffc 0f28c7 }
            // n = 5, score = 200
            //   0f2965c0             | movaps              xmmword ptr [ebp - 0x40], xmm4
            //   3bce                 | cmp                 ecx, esi
            //   0f8cfcfeffff         | jl                  0xffffff02
            //   660f383ffc           | pmaxud              xmm7, xmm4
            //   0f28c7               | movaps              xmm0, xmm7

        $sequence_9 = { 56 57 8bda 8bf9 0fb707 8d7f02 }
            // n = 6, score = 200
            //   56                   | push                esi
            //   57                   | push                edi
            //   8bda                 | mov                 ebx, edx
            //   8bf9                 | mov                 edi, ecx
            //   0fb707               | movzx               eax, word ptr [edi]
            //   8d7f02               | lea                 edi, dword ptr [edi + 2]

        $sequence_10 = { 0fb607 8d7f01 8bca c1e208 c1e918 33c8 33948d00fcffff }
            // n = 7, score = 200
            //   0fb607               | movzx               eax, byte ptr [edi]
            //   8d7f01               | lea                 edi, dword ptr [edi + 1]
            //   8bca                 | mov                 ecx, edx
            //   c1e208               | shl                 edx, 8
            //   c1e918               | shr                 ecx, 0x18
            //   33c8                 | xor                 ecx, eax
            //   33948d00fcffff       | xor                 edx, dword ptr [ebp + ecx*4 - 0x400]

        $sequence_11 = { 8bc1 8945fc 85c0 0f84f8000000 8b480c 85c9 }
            // n = 6, score = 200
            //   8bc1                 | mov                 eax, ecx
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   85c0                 | test                eax, eax
            //   0f84f8000000         | je                  0xfe
            //   8b480c               | mov                 ecx, dword ptr [eax + 0xc]
            //   85c9                 | test                ecx, ecx

        $sequence_12 = { c745c46c6c6f63 c645c800 ffd3 837e0400 89460c 745d 8d45dc }
            // n = 7, score = 200
            //   c745c46c6c6f63       | mov                 dword ptr [ebp - 0x3c], 0x636f6c6c
            //   c645c800             | mov                 byte ptr [ebp - 0x38], 0
            //   ffd3                 | call                ebx
            //   837e0400             | cmp                 dword ptr [esi + 4], 0
            //   89460c               | mov                 dword ptr [esi + 0xc], eax
            //   745d                 | je                  0x5f
            //   8d45dc               | lea                 eax, dword ptr [ebp - 0x24]

        $sequence_13 = { 8b4318 57 6a1c 6a40 ffd0 }
            // n = 5, score = 200
            //   8b4318               | mov                 eax, dword ptr [ebx + 0x18]
            //   57                   | push                edi
            //   6a1c                 | push                0x1c
            //   6a40                 | push                0x40
            //   ffd0                 | call                eax

        $sequence_14 = { 48 83c8f8 40 8bf2 0f57ff 2bf0 0f28e7 }
            // n = 7, score = 200
            //   48                   | dec                 eax
            //   83c8f8               | or                  eax, 0xfffffff8
            //   40                   | inc                 eax
            //   8bf2                 | mov                 esi, edx
            //   0f57ff               | xorps               xmm7, xmm7
            //   2bf0                 | sub                 esi, eax
            //   0f28e7               | movaps              xmm4, xmm7

        $sequence_15 = { c745e400000000 895df8 895de8 85c9 747a 8b4614 }
            // n = 6, score = 200
            //   c745e400000000       | mov                 dword ptr [ebp - 0x1c], 0
            //   895df8               | mov                 dword ptr [ebp - 8], ebx
            //   895de8               | mov                 dword ptr [ebp - 0x18], ebx
            //   85c9                 | test                ecx, ecx
            //   747a                 | je                  0x7c
            //   8b4614               | mov                 eax, dword ptr [esi + 0x14]

    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
}