rule win_fickerstealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.fickerstealer."
        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.fickerstealer"
        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 = { 8dbc24a4040000 f3ab 8d8424a4040000 8d8c24a0040000 f20f108424001d0000 f20f108c24081d0000 f20f118888000000 }
            // n = 7, score = 200
            //   8dbc24a4040000       | lea                 edi, [esp + 0x4a4]
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax
            //   8d8424a4040000       | lea                 eax, [esp + 0x4a4]
            //   8d8c24a0040000       | lea                 ecx, [esp + 0x4a0]
            //   f20f108424001d0000     | movsd    xmm0, qword ptr [esp + 0x1d00]
            //   f20f108c24081d0000     | movsd    xmm1, qword ptr [esp + 0x1d08]
            //   f20f118888000000     | movsd               qword ptr [eax + 0x88], xmm1

        $sequence_1 = { 5d e9???????? 5d c3 55 89e5 8b4104 }
            // n = 7, score = 200
            //   5d                   | pop                 ebp
            //   e9????????           |                     
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   55                   | push                ebp
            //   89e5                 | mov                 ebp, esp
            //   8b4104               | mov                 eax, dword ptr [ecx + 4]

        $sequence_2 = { ff7008 e8???????? 58 5e 5d c3 55 }
            // n = 7, score = 200
            //   ff7008               | push                dword ptr [eax + 8]
            //   e8????????           |                     
            //   58                   | pop                 eax
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   55                   | push                ebp

        $sequence_3 = { 53 57 56 50 8b4104 8955f0 89cf }
            // n = 7, score = 200
            //   53                   | push                ebx
            //   57                   | push                edi
            //   56                   | push                esi
            //   50                   | push                eax
            //   8b4104               | mov                 eax, dword ptr [ecx + 4]
            //   8955f0               | mov                 dword ptr [ebp - 0x10], edx
            //   89cf                 | mov                 edi, ecx

        $sequence_4 = { e8???????? 83c414 8b07 8b5704 8d65f8 5e 5f }
            // n = 7, score = 200
            //   e8????????           |                     
            //   83c414               | add                 esp, 0x14
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   8b5704               | mov                 edx, dword ptr [edi + 4]
            //   8d65f8               | lea                 esp, [ebp - 8]
            //   5e                   | pop                 esi
            //   5f                   | pop                 edi

        $sequence_5 = { e9???????? 55 89e5 51 e8???????? 5d c3 }
            // n = 7, score = 200
            //   e9????????           |                     
            //   55                   | push                ebp
            //   89e5                 | mov                 ebp, esp
            //   51                   | push                ecx
            //   e8????????           |                     
            //   5d                   | pop                 ebp
            //   c3                   | ret                 

        $sequence_6 = { 894108 f20f1101 6a05 5a e8???????? 832600 83660400 }
            // n = 7, score = 200
            //   894108               | mov                 dword ptr [ecx + 8], eax
            //   f20f1101             | movsd               qword ptr [ecx], xmm0
            //   6a05                 | push                5
            //   5a                   | pop                 edx
            //   e8????????           |                     
            //   832600               | and                 dword ptr [esi], 0
            //   83660400             | and                 dword ptr [esi + 4], 0

        $sequence_7 = { e8???????? 8b4e04 89d7 8945f0 85c9 7414 8b16 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   8b4e04               | mov                 ecx, dword ptr [esi + 4]
            //   89d7                 | mov                 edi, edx
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   85c9                 | test                ecx, ecx
            //   7414                 | je                  0x16
            //   8b16                 | mov                 edx, dword ptr [esi]

        $sequence_8 = { 8d949480150000 33048a 89f1 8d5601 21fe 21d9 8d8c8c80150000 }
            // n = 7, score = 200
            //   8d949480150000       | lea                 edx, [esp + edx*4 + 0x1580]
            //   33048a               | xor                 eax, dword ptr [edx + ecx*4]
            //   89f1                 | mov                 ecx, esi
            //   8d5601               | lea                 edx, [esi + 1]
            //   21fe                 | and                 esi, edi
            //   21d9                 | and                 ecx, ebx
            //   8d8c8c80150000       | lea                 ecx, [esp + ecx*4 + 0x1580]

        $sequence_9 = { f20f104808 f20f114610 f20f114e08 f20f1116 56 e8???????? 59 }
            // n = 7, score = 200
            //   f20f104808           | movsd               xmm1, qword ptr [eax + 8]
            //   f20f114610           | movsd               qword ptr [esi + 0x10], xmm0
            //   f20f114e08           | movsd               qword ptr [esi + 8], xmm1
            //   f20f1116             | movsd               qword ptr [esi], xmm2
            //   56                   | push                esi
            //   e8????????           |                     
            //   59                   | pop                 ecx

    condition:
        7 of them and filesize < 598016
}

rule win_fickerstealer_w0 {
  meta: 
    author = "Ben Cohen, CyberArk"
    date = "22-02-2021"
    version = "1.0"
    hash = "a4113ccb55e06e783b6cb213647614f039aa7dbb454baa338459ccf37897ebd6"
    source = "https://github.com/cyberark/malware-research/blob/master/FickerStealer/Ficker_Stealer.yar"
    description = "Yara rule for Ficker Stealer"
    malpedia_rule_date = "20210726"
    malpedia_hash = ""
    malpedia_version = "20210726"
    malpedia_license = "CC BY-NC-SA 4.0"
    malpedia_sharing = "TLP:WHITE"
    malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.fickerstealer"
  
  strings:
    //$decryption_pattern = { 89 ?? C1 ?? ?? 31 ?? 89 ?? C1 ?? ?? 31 ?? 8B ?? ?? 89 ?? C1 ?? ?? 31 }
    $c2_const = { 0C 00 0F 0A [0-4] 0B 0A 0B 0A }

    $s1 = "kindmessage"
    $s2 = "SomeNone"
    $s3 = ".Kind"

  condition:
    //$decryption_pattern and
    $c2_const and
    (1 of ($s*)) and
    uint16(0) == 0x5A4D
}