rule win_jssloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        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 = "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 = { c78564ffffff00000000 c68568ffffff00 e8???????? 8d859cfeffff }
            // n = 4, score = 200
            //   c78564ffffff00000000     | mov    dword ptr [ebp - 0x9c], 0
            //   c68568ffffff00       | mov                 byte ptr [ebp - 0x98], 0
            //   e8????????           |                     
            //   8d859cfeffff         | lea                 eax, [ebp - 0x164]

        $sequence_1 = { 50 8b45e0 8b08 e8???????? 84c0 c645fc00 8b55cc }
            // n = 7, score = 200
            //   50                   | push                eax
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   e8????????           |                     
            //   84c0                 | test                al, al
            //   c645fc00             | mov                 byte ptr [ebp - 4], 0
            //   8b55cc               | mov                 edx, dword ptr [ebp - 0x34]

        $sequence_2 = { 8b7dc0 8b45b0 0f43d7 8b75ac 2bc6 }
            // n = 5, score = 200
            //   8b7dc0               | mov                 edi, dword ptr [ebp - 0x40]
            //   8b45b0               | mov                 eax, dword ptr [ebp - 0x50]
            //   0f43d7               | cmovae              edx, edi
            //   8b75ac               | mov                 esi, dword ptr [ebp - 0x54]
            //   2bc6                 | sub                 eax, esi

        $sequence_3 = { 8bcf 83e73f c1f906 6bd738 8b0c8d701d4400 }
            // n = 5, score = 200
            //   8bcf                 | mov                 ecx, edi
            //   83e73f               | and                 edi, 0x3f
            //   c1f906               | sar                 ecx, 6
            //   6bd738               | imul                edx, edi, 0x38
            //   8b0c8d701d4400       | mov                 ecx, dword ptr [ecx*4 + 0x441d70]

        $sequence_4 = { 8b85f8feffff c745d000000000 c745d40f000000 c645c000 8b4004 c78405f8feffffa8be4300 8b85f8feffff }
            // n = 7, score = 200
            //   8b85f8feffff         | mov                 eax, dword ptr [ebp - 0x108]
            //   c745d000000000       | mov                 dword ptr [ebp - 0x30], 0
            //   c745d40f000000       | mov                 dword ptr [ebp - 0x2c], 0xf
            //   c645c000             | mov                 byte ptr [ebp - 0x40], 0
            //   8b4004               | mov                 eax, dword ptr [eax + 4]
            //   c78405f8feffffa8be4300     | mov    dword ptr [ebp + eax - 0x108], 0x43bea8
            //   8b85f8feffff         | mov                 eax, dword ptr [ebp - 0x108]

        $sequence_5 = { 50 8d4dd4 e8???????? 8985b8feffff beffffff7f c645fc0e 8b55cc }
            // n = 7, score = 200
            //   50                   | push                eax
            //   8d4dd4               | lea                 ecx, [ebp - 0x2c]
            //   e8????????           |                     
            //   8985b8feffff         | mov                 dword ptr [ebp - 0x148], eax
            //   beffffff7f           | mov                 esi, 0x7fffffff
            //   c645fc0e             | mov                 byte ptr [ebp - 4], 0xe
            //   8b55cc               | mov                 edx, dword ptr [ebp - 0x34]

        $sequence_6 = { 7408 40 83f81d 7cf1 eb07 8b0cc57c3f4300 894de4 }
            // n = 7, score = 200
            //   7408                 | je                  0xa
            //   40                   | inc                 eax
            //   83f81d               | cmp                 eax, 0x1d
            //   7cf1                 | jl                  0xfffffff3
            //   eb07                 | jmp                 9
            //   8b0cc57c3f4300       | mov                 ecx, dword ptr [eax*8 + 0x433f7c]
            //   894de4               | mov                 dword ptr [ebp - 0x1c], ecx

        $sequence_7 = { 83f810 7231 8b953cffffff 8d4801 8bc2 }
            // n = 5, score = 200
            //   83f810               | cmp                 eax, 0x10
            //   7231                 | jb                  0x33
            //   8b953cffffff         | mov                 edx, dword ptr [ebp - 0xc4]
            //   8d4801               | lea                 ecx, [eax + 1]
            //   8bc2                 | mov                 eax, edx

        $sequence_8 = { e8???????? 8be5 5d c20c00 8b854cfeffff 8d4804 }
            // n = 6, score = 200
            //   e8????????           |                     
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c20c00               | ret                 0xc
            //   8b854cfeffff         | mov                 eax, dword ptr [ebp - 0x1b4]
            //   8d4804               | lea                 ecx, [eax + 4]

        $sequence_9 = { b8abaaaa2a 2bcf 895df0 f7e9 8b4b04 c1fa03 2bcf }
            // n = 7, score = 200
            //   b8abaaaa2a           | mov                 eax, 0x2aaaaaab
            //   2bcf                 | sub                 ecx, edi
            //   895df0               | mov                 dword ptr [ebp - 0x10], ebx
            //   f7e9                 | imul                ecx
            //   8b4b04               | mov                 ecx, dword ptr [ebx + 4]
            //   c1fa03               | sar                 edx, 3
            //   2bcf                 | sub                 ecx, edi

    condition:
        7 of them and filesize < 581632
}