rule win_fickerstealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        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 = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { c70201000000 894a08 894204 eb0e 8b4df0 89d8 2b45ec }
            // n = 7, score = 200
            //   c70201000000         | mov                 dword ptr [edx], 1
            //   894a08               | mov                 dword ptr [edx + 8], ecx
            //   894204               | mov                 dword ptr [edx + 4], eax
            //   eb0e                 | jmp                 0x10
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]
            //   89d8                 | mov                 eax, ebx
            //   2b45ec               | sub                 eax, dword ptr [ebp - 0x14]

        $sequence_1 = { 83a4240802000000 e8???????? 6a08 58 8b4d08 e9???????? 8d842418020000 }
            // n = 7, score = 200
            //   83a4240802000000     | and                 dword ptr [esp + 0x208], 0
            //   e8????????           |                     
            //   6a08                 | push                8
            //   58                   | pop                 eax
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   e9????????           |                     
            //   8d842418020000       | lea                 eax, [esp + 0x218]

        $sequence_2 = { 8919 895104 894108 e8???????? 894604 31c0 895608 }
            // n = 7, score = 200
            //   8919                 | mov                 dword ptr [ecx], ebx
            //   895104               | mov                 dword ptr [ecx + 4], edx
            //   894108               | mov                 dword ptr [ecx + 8], eax
            //   e8????????           |                     
            //   894604               | mov                 dword ptr [esi + 4], eax
            //   31c0                 | xor                 eax, eax
            //   895608               | mov                 dword ptr [esi + 8], edx

        $sequence_3 = { 5e 5d c3 89c1 52 56 e8???????? }
            // n = 7, score = 200
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   89c1                 | mov                 ecx, eax
            //   52                   | push                edx
            //   56                   | push                esi
            //   e8????????           |                     

        $sequence_4 = { 0d0000f07f 660f6ec0 e9???????? 8b4d0c 89c6 89ca 21da }
            // n = 7, score = 200
            //   0d0000f07f           | or                  eax, 0x7ff00000
            //   660f6ec0             | movd                xmm0, eax
            //   e9????????           |                     
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   89c6                 | mov                 esi, eax
            //   89ca                 | mov                 edx, ecx
            //   21da                 | and                 edx, ebx

        $sequence_5 = { f20f1000 f20f104808 8d45e4 09f1 8d75d4 894d94 89f1 }
            // n = 7, score = 200
            //   f20f1000             | movsd               xmm0, qword ptr [eax]
            //   f20f104808           | movsd               xmm1, qword ptr [eax + 8]
            //   8d45e4               | lea                 eax, [ebp - 0x1c]
            //   09f1                 | or                  ecx, esi
            //   8d75d4               | lea                 esi, [ebp - 0x2c]
            //   894d94               | mov                 dword ptr [ebp - 0x6c], ecx
            //   89f1                 | mov                 ecx, esi

        $sequence_6 = { e8???????? 50 e8???????? 5e 5d c3 55 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   50                   | push                eax
            //   e8????????           |                     
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   55                   | push                ebp

        $sequence_7 = { 8d8c2400010000 e8???????? 8d8c2444010000 e8???????? 897c2408 89742404 31ff }
            // n = 7, score = 200
            //   8d8c2400010000       | lea                 ecx, [esp + 0x100]
            //   e8????????           |                     
            //   8d8c2444010000       | lea                 ecx, [esp + 0x144]
            //   e8????????           |                     
            //   897c2408             | mov                 dword ptr [esp + 8], edi
            //   89742404             | mov                 dword ptr [esp + 4], esi
            //   31ff                 | xor                 edi, edi

        $sequence_8 = { 8b4dec e8???????? eb2a 31d2 eb18 85c9 7412 }
            // n = 7, score = 200
            //   8b4dec               | mov                 ecx, dword ptr [ebp - 0x14]
            //   e8????????           |                     
            //   eb2a                 | jmp                 0x2c
            //   31d2                 | xor                 edx, edx
            //   eb18                 | jmp                 0x1a
            //   85c9                 | test                ecx, ecx
            //   7412                 | je                  0x14

        $sequence_9 = { a820 b900000000 0f45fe 0f45f1 247f 3c40 0f43f9 }
            // n = 7, score = 200
            //   a820                 | test                al, 0x20
            //   b900000000           | mov                 ecx, 0
            //   0f45fe               | cmovne              edi, esi
            //   0f45f1               | cmovne              esi, ecx
            //   247f                 | and                 al, 0x7f
            //   3c40                 | cmp                 al, 0x40
            //   0f43f9               | cmovae              edi, 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
}