rule win_jssloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.jssloader."
        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.jssloader"
        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 = { 7424 66660f1f840000000000 8b07 8d8dbcfeffff 8a1430 e8???????? 8b4704 }
            // n = 7, score = 200
            //   7424                 | je                  0x26
            //   66660f1f840000000000     | nop    word ptr [eax + eax]
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   8d8dbcfeffff         | lea                 ecx, [ebp - 0x144]
            //   8a1430               | mov                 dl, byte ptr [eax + esi]
            //   e8????????           |                     
            //   8b4704               | mov                 eax, dword ptr [edi + 4]

        $sequence_1 = { 33db 43 33ff 8b0485701d4400 }
            // n = 4, score = 200
            //   33db                 | xor                 ebx, ebx
            //   43                   | inc                 ebx
            //   33ff                 | xor                 edi, edi
            //   8b0485701d4400       | mov                 eax, dword ptr [eax*4 + 0x441d70]

        $sequence_2 = { 683f000f00 6a00 68???????? 89b5d0feffff }
            // n = 4, score = 200
            //   683f000f00           | push                0xf003f
            //   6a00                 | push                0
            //   68????????           |                     
            //   89b5d0feffff         | mov                 dword ptr [ebp - 0x130], esi

        $sequence_3 = { 8b853cffffff 8b10 85d2 741a }
            // n = 4, score = 200
            //   8b853cffffff         | mov                 eax, dword ptr [ebp - 0xc4]
            //   8b10                 | mov                 edx, dword ptr [eax]
            //   85d2                 | test                edx, edx
            //   741a                 | je                  0x1c

        $sequence_4 = { 722a 83fa10 8d75cc 8d4103 0f4375cc }
            // n = 5, score = 200
            //   722a                 | jb                  0x2c
            //   83fa10               | cmp                 edx, 0x10
            //   8d75cc               | lea                 esi, [ebp - 0x34]
            //   8d4103               | lea                 eax, [ecx + 3]
            //   0f4375cc             | cmovae              esi, dword ptr [ebp - 0x34]

        $sequence_5 = { 0f873e010000 52 51 e8???????? 83c408 c7458400000000 c745880f000000 }
            // n = 7, score = 200
            //   0f873e010000         | ja                  0x144
            //   52                   | push                edx
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   c7458400000000       | mov                 dword ptr [ebp - 0x7c], 0
            //   c745880f000000       | mov                 dword ptr [ebp - 0x78], 0xf

        $sequence_6 = { e8???????? 8bc8 c645fc07 8b7114 8bc6 8b5110 2bc2 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   8bc8                 | mov                 ecx, eax
            //   c645fc07             | mov                 byte ptr [ebp - 4], 7
            //   8b7114               | mov                 esi, dword ptr [ecx + 0x14]
            //   8bc6                 | mov                 eax, esi
            //   8b5110               | mov                 edx, dword ptr [ecx + 0x10]
            //   2bc2                 | sub                 eax, edx

        $sequence_7 = { 75b9 5f 5e 5d c3 e8???????? cc }
            // n = 7, score = 200
            //   75b9                 | jne                 0xffffffbb
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   e8????????           |                     
            //   cc                   | int3                

        $sequence_8 = { c645fc09 50 e8???????? c785b4feffffa0bb4300 c745ec0f000000 83ec18 c645fc0c }
            // n = 7, score = 200
            //   c645fc09             | mov                 byte ptr [ebp - 4], 9
            //   50                   | push                eax
            //   e8????????           |                     
            //   c785b4feffffa0bb4300     | mov    dword ptr [ebp - 0x14c], 0x43bba0
            //   c745ec0f000000       | mov                 dword ptr [ebp - 0x14], 0xf
            //   83ec18               | sub                 esp, 0x18
            //   c645fc0c             | mov                 byte ptr [ebp - 4], 0xc

        $sequence_9 = { c78594fbffff00000000 660fd6858cfbffff c7858cfbffff00000000 c78590fbffff00000000 c78594fbffff00000000 33d2 }
            // n = 6, score = 200
            //   c78594fbffff00000000     | mov    dword ptr [ebp - 0x46c], 0
            //   660fd6858cfbffff     | movq                qword ptr [ebp - 0x474], xmm0
            //   c7858cfbffff00000000     | mov    dword ptr [ebp - 0x474], 0
            //   c78590fbffff00000000     | mov    dword ptr [ebp - 0x470], 0
            //   c78594fbffff00000000     | mov    dword ptr [ebp - 0x46c], 0
            //   33d2                 | xor                 edx, edx

    condition:
        7 of them and filesize < 581632
}