rule win_jaff_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.jaff."
        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.jaff"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { 83c418 4e 79cc 837f0400 5e }
            // n = 5, score = 600
            //   83c418               | add                 esp, 0x18
            //   4e                   | dec                 esi
            //   79cc                 | jns                 0xffffffce
            //   837f0400             | cmp                 dword ptr [edi + 4], 0
            //   5e                   | pop                 esi

        $sequence_1 = { 8d4c0701 51 6a08 ff15???????? 50 ff15???????? 8bf0 }
            // n = 7, score = 600
            //   8d4c0701             | lea                 ecx, [edi + eax + 1]
            //   51                   | push                ecx
            //   6a08                 | push                8
            //   ff15????????         |                     
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8bf0                 | mov                 esi, eax

        $sequence_2 = { 81ec08040000 56 57 33ff 8bf1 897e04 c6460c01 }
            // n = 7, score = 600
            //   81ec08040000         | sub                 esp, 0x408
            //   56                   | push                esi
            //   57                   | push                edi
            //   33ff                 | xor                 edi, edi
            //   8bf1                 | mov                 esi, ecx
            //   897e04               | mov                 dword ptr [esi + 4], edi
            //   c6460c01             | mov                 byte ptr [esi + 0xc], 1

        $sequence_3 = { c745c40a000000 c645c801 ffd3 50 ffd7 }
            // n = 5, score = 600
            //   c745c40a000000       | mov                 dword ptr [ebp - 0x3c], 0xa
            //   c645c801             | mov                 byte ptr [ebp - 0x38], 1
            //   ffd3                 | call                ebx
            //   50                   | push                eax
            //   ffd7                 | call                edi

        $sequence_4 = { 8d4dfc 51 52 50 56 ffd7 }
            // n = 6, score = 600
            //   8d4dfc               | lea                 ecx, [ebp - 4]
            //   51                   | push                ecx
            //   52                   | push                edx
            //   50                   | push                eax
            //   56                   | push                esi
            //   ffd7                 | call                edi

        $sequence_5 = { 7408 3c38 7404 3c39 754a 8845fc 8d45fc }
            // n = 7, score = 600
            //   7408                 | je                  0xa
            //   3c38                 | cmp                 al, 0x38
            //   7404                 | je                  6
            //   3c39                 | cmp                 al, 0x39
            //   754a                 | jne                 0x4c
            //   8845fc               | mov                 byte ptr [ebp - 4], al
            //   8d45fc               | lea                 eax, [ebp - 4]

        $sequence_6 = { 66891c3a 83c202 49 79f0 50 6a00 ff15???????? }
            // n = 7, score = 600
            //   66891c3a             | mov                 word ptr [edx + edi], bx
            //   83c202               | add                 edx, 2
            //   49                   | dec                 ecx
            //   79f0                 | jns                 0xfffffff2
            //   50                   | push                eax
            //   6a00                 | push                0
            //   ff15????????         |                     

        $sequence_7 = { 0f85b0000000 68080000f0 6a18 57 57 8d4dfc }
            // n = 6, score = 600
            //   0f85b0000000         | jne                 0xb6
            //   68080000f0           | push                0xf0000008
            //   6a18                 | push                0x18
            //   57                   | push                edi
            //   57                   | push                edi
            //   8d4dfc               | lea                 ecx, [ebp - 4]

        $sequence_8 = { 8b4f04 83ec10 8bf4 894e04 8b5708 8bca }
            // n = 6, score = 600
            //   8b4f04               | mov                 ecx, dword ptr [edi + 4]
            //   83ec10               | sub                 esp, 0x10
            //   8bf4                 | mov                 esi, esp
            //   894e04               | mov                 dword ptr [esi + 4], ecx
            //   8b5708               | mov                 edx, dword ptr [edi + 8]
            //   8bca                 | mov                 ecx, edx

        $sequence_9 = { 83fe0a 7438 8a8c3598fbffff 8d55fc }
            // n = 4, score = 600
            //   83fe0a               | cmp                 esi, 0xa
            //   7438                 | je                  0x3a
            //   8a8c3598fbffff       | mov                 cl, byte ptr [ebp + esi - 0x468]
            //   8d55fc               | lea                 edx, [ebp - 4]

    condition:
        7 of them and filesize < 106496
}