rule win_nimgrabber_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.nimgrabber."
        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.nimgrabber"
        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 = { 894c2404 891424 83c001 89442408 e8???????? 8b03 0306 }
            // n = 7, score = 200
            //   894c2404             | mov                 dword ptr [esp + 4], ecx
            //   891424               | mov                 dword ptr [esp], edx
            //   83c001               | add                 eax, 1
            //   89442408             | mov                 dword ptr [esp + 8], eax
            //   e8????????           |                     
            //   8b03                 | mov                 eax, dword ptr [ebx]
            //   0306                 | add                 eax, dword ptr [esi]

        $sequence_1 = { 0fb7c0 0fb6542e08 c1e206 81e2c00f0000 09d0 0fb6543e08 83e23f }
            // n = 7, score = 200
            //   0fb7c0               | movzx               eax, ax
            //   0fb6542e08           | movzx               edx, byte ptr [esi + ebp + 8]
            //   c1e206               | shl                 edx, 6
            //   81e2c00f0000         | and                 edx, 0xfc0
            //   09d0                 | or                  eax, edx
            //   0fb6543e08           | movzx               edx, byte ptr [esi + edi + 8]
            //   83e23f               | and                 edx, 0x3f

        $sequence_2 = { c744241008000000 c1eb08 be08000000 e9???????? c744241009000000 c1eb07 be09000000 }
            // n = 7, score = 200
            //   c744241008000000     | mov                 dword ptr [esp + 0x10], 8
            //   c1eb08               | shr                 ebx, 8
            //   be08000000           | mov                 esi, 8
            //   e9????????           |                     
            //   c744241009000000     | mov                 dword ptr [esp + 0x10], 9
            //   c1eb07               | shr                 ebx, 7
            //   be09000000           | mov                 esi, 9

        $sequence_3 = { 0f87fc0a0000 395f6c 0f87080b0000 395f70 0f87140b0000 395f74 0f87200b0000 }
            // n = 7, score = 200
            //   0f87fc0a0000         | ja                  0xb02
            //   395f6c               | cmp                 dword ptr [edi + 0x6c], ebx
            //   0f87080b0000         | ja                  0xb0e
            //   395f70               | cmp                 dword ptr [edi + 0x70], ebx
            //   0f87140b0000         | ja                  0xb1a
            //   395f74               | cmp                 dword ptr [edi + 0x74], ebx
            //   0f87200b0000         | ja                  0xb26

        $sequence_4 = { 3b5f44 0f82010a0000 3b5f48 0f820d0a0000 3b5f4c 0f822e0a0000 }
            // n = 6, score = 200
            //   3b5f44               | cmp                 ebx, dword ptr [edi + 0x44]
            //   0f82010a0000         | jb                  0xa07
            //   3b5f48               | cmp                 ebx, dword ptr [edi + 0x48]
            //   0f820d0a0000         | jb                  0xa13
            //   3b5f4c               | cmp                 ebx, dword ptr [edi + 0x4c]
            //   0f822e0a0000         | jb                  0xa34

        $sequence_5 = { 0f8fcffeffff 89fd 8b5504 89e9 e8???????? 8d4d04 89da }
            // n = 7, score = 200
            //   0f8fcffeffff         | jg                  0xfffffed5
            //   89fd                 | mov                 ebp, edi
            //   8b5504               | mov                 edx, dword ptr [ebp + 4]
            //   89e9                 | mov                 ecx, ebp
            //   e8????????           |                     
            //   8d4d04               | lea                 ecx, [ebp + 4]
            //   89da                 | mov                 edx, ebx

        $sequence_6 = { 8b03 83ec0c 89c7 83ef08 0f80d9050000 83e804 8b6c3b08 }
            // n = 7, score = 200
            //   8b03                 | mov                 eax, dword ptr [ebx]
            //   83ec0c               | sub                 esp, 0xc
            //   89c7                 | mov                 edi, eax
            //   83ef08               | sub                 edi, 8
            //   0f80d9050000         | jo                  0x5df
            //   83e804               | sub                 eax, 4
            //   8b6c3b08             | mov                 ebp, dword ptr [ebx + edi + 8]

        $sequence_7 = { 8b00 89842488000000 85c0 0f8eab1a0000 8b44246c 31db }
            // n = 6, score = 200
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   89842488000000       | mov                 dword ptr [esp + 0x88], eax
            //   85c0                 | test                eax, eax
            //   0f8eab1a0000         | jle                 0x1ab1
            //   8b44246c             | mov                 eax, dword ptr [esp + 0x6c]
            //   31db                 | xor                 ebx, ebx

        $sequence_8 = { 894d14 894500 895508 83fa38 7f08 8b7c241c 3907 }
            // n = 7, score = 200
            //   894d14               | mov                 dword ptr [ebp + 0x14], ecx
            //   894500               | mov                 dword ptr [ebp], eax
            //   895508               | mov                 dword ptr [ebp + 8], edx
            //   83fa38               | cmp                 edx, 0x38
            //   7f08                 | jg                  0xa
            //   8b7c241c             | mov                 edi, dword ptr [esp + 0x1c]
            //   3907                 | cmp                 dword ptr [edi], eax

        $sequence_9 = { e9???????? e8???????? e9???????? 894c2414 e8???????? 8b4c2414 e9???????? }
            // n = 7, score = 200
            //   e9????????           |                     
            //   e8????????           |                     
            //   e9????????           |                     
            //   894c2414             | mov                 dword ptr [esp + 0x14], ecx
            //   e8????????           |                     
            //   8b4c2414             | mov                 ecx, dword ptr [esp + 0x14]
            //   e9????????           |                     

    condition:
        7 of them and filesize < 1238016
}