rule win_lookback_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        version = "1"
        description = "Detects win.lookback."
        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.lookback"
        malpedia_rule_date = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 8b54241c 33c0 668b0469 8b0482 03c7 5f }
            // n = 6, score = 200
            //   8b54241c             | mov                 edx, dword ptr [esp + 0x1c]
            //   33c0                 | xor                 eax, eax
            //   668b0469             | mov                 ax, word ptr [ecx + ebp*2]
            //   8b0482               | mov                 eax, dword ptr [edx + eax*4]
            //   03c7                 | add                 eax, edi
            //   5f                   | pop                 edi

        $sequence_1 = { 33c0 894c2406 89442412 894c240a }
            // n = 4, score = 200
            //   33c0                 | xor                 eax, eax
            //   894c2406             | mov                 dword ptr [esp + 6], ecx
            //   89442412             | mov                 dword ptr [esp + 0x12], eax
            //   894c240a             | mov                 dword ptr [esp + 0xa], ecx

        $sequence_2 = { 8b08 894d00 668b5004 66895504 53 e8???????? 83c404 }
            // n = 7, score = 200
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   894d00               | mov                 dword ptr [ebp], ecx
            //   668b5004             | mov                 dx, word ptr [eax + 4]
            //   66895504             | mov                 word ptr [ebp + 4], dx
            //   53                   | push                ebx
            //   e8????????           |                     
            //   83c404               | add                 esp, 4

        $sequence_3 = { 50 ffd3 393d???????? 75af eb24 8b0d???????? }
            // n = 6, score = 200
            //   50                   | push                eax
            //   ffd3                 | call                ebx
            //   393d????????         |                     
            //   75af                 | jne                 0xffffffb1
            //   eb24                 | jmp                 0x26
            //   8b0d????????         |                     

        $sequence_4 = { 66894c2416 89442422 8bfa 83c9ff f2ae }
            // n = 5, score = 200
            //   66894c2416           | mov                 word ptr [esp + 0x16], cx
            //   89442422             | mov                 dword ptr [esp + 0x22], eax
            //   8bfa                 | mov                 edi, edx
            //   83c9ff               | or                  ecx, 0xffffffff
            //   f2ae                 | repne scasb         al, byte ptr es:[edi]

        $sequence_5 = { c644240800 88442415 e8???????? 8d4c240c 89442408 51 }
            // n = 6, score = 200
            //   c644240800           | mov                 byte ptr [esp + 8], 0
            //   88442415             | mov                 byte ptr [esp + 0x15], al
            //   e8????????           |                     
            //   8d4c240c             | lea                 ecx, dword ptr [esp + 0xc]
            //   89442408             | mov                 dword ptr [esp + 8], eax
            //   51                   | push                ecx

        $sequence_6 = { 89742424 e8???????? 8bce 8bd8 8bd1 33c0 }
            // n = 6, score = 200
            //   89742424             | mov                 dword ptr [esp + 0x24], esi
            //   e8????????           |                     
            //   8bce                 | mov                 ecx, esi
            //   8bd8                 | mov                 ebx, eax
            //   8bd1                 | mov                 edx, ecx
            //   33c0                 | xor                 eax, eax

        $sequence_7 = { 889c041b010000 880e 72bc 8bac2424070000 }
            // n = 4, score = 200
            //   889c041b010000       | mov                 byte ptr [esp + eax + 0x11b], bl
            //   880e                 | mov                 byte ptr [esi], cl
            //   72bc                 | jb                  0xffffffbe
            //   8bac2424070000       | mov                 ebp, dword ptr [esp + 0x724]

        $sequence_8 = { 83c420 c3 5f 33c0 5b }
            // n = 5, score = 200
            //   83c420               | add                 esp, 0x20
            //   c3                   | ret                 
            //   5f                   | pop                 edi
            //   33c0                 | xor                 eax, eax
            //   5b                   | pop                 ebx

        $sequence_9 = { 668b4b06 3be9 7cd0 5f 5e }
            // n = 5, score = 200
            //   668b4b06             | mov                 cx, word ptr [ebx + 6]
            //   3be9                 | cmp                 ebp, ecx
            //   7cd0                 | jl                  0xffffffd2
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

    condition:
        7 of them and filesize < 131072
}