rule win_netrepser_keylogger_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.netrepser_keylogger."
        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.netrepser_keylogger"
        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 = { 0fb78decfeffff 51 0fb795eafeffff 52 0fb785e6feffff 50 }
            // n = 6, score = 200
            //   0fb78decfeffff       | movzx               ecx, word ptr [ebp - 0x114]
            //   51                   | push                ecx
            //   0fb795eafeffff       | movzx               edx, word ptr [ebp - 0x116]
            //   52                   | push                edx
            //   0fb785e6feffff       | movzx               eax, word ptr [ebp - 0x11a]
            //   50                   | push                eax

        $sequence_1 = { e8???????? 83c408 8b55f8 52 a1???????? 8b4840 ffd1 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   8b55f8               | mov                 edx, dword ptr [ebp - 8]
            //   52                   | push                edx
            //   a1????????           |                     
            //   8b4840               | mov                 ecx, dword ptr [eax + 0x40]
            //   ffd1                 | call                ecx

        $sequence_2 = { b801000000 e9???????? 6a10 8d55f0 }
            // n = 4, score = 200
            //   b801000000           | mov                 eax, 1
            //   e9????????           |                     
            //   6a10                 | push                0x10
            //   8d55f0               | lea                 edx, [ebp - 0x10]

        $sequence_3 = { 7420 8b4508 0345fc 0fbe08 85c9 7413 8b55fc }
            // n = 7, score = 200
            //   7420                 | je                  0x22
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   0345fc               | add                 eax, dword ptr [ebp - 4]
            //   0fbe08               | movsx               ecx, byte ptr [eax]
            //   85c9                 | test                ecx, ecx
            //   7413                 | je                  0x15
            //   8b55fc               | mov                 edx, dword ptr [ebp - 4]

        $sequence_4 = { 83c001 8945f8 8b4df8 3b4dfc 737d 8b550c }
            // n = 6, score = 200
            //   83c001               | add                 eax, 1
            //   8945f8               | mov                 dword ptr [ebp - 8], eax
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   3b4dfc               | cmp                 ecx, dword ptr [ebp - 4]
            //   737d                 | jae                 0x7f
            //   8b550c               | mov                 edx, dword ptr [ebp + 0xc]

        $sequence_5 = { 52 8d8530f8ffff 50 8d8d88f8ffff 51 6a00 6a10 }
            // n = 7, score = 200
            //   52                   | push                edx
            //   8d8530f8ffff         | lea                 eax, [ebp - 0x7d0]
            //   50                   | push                eax
            //   8d8d88f8ffff         | lea                 ecx, [ebp - 0x778]
            //   51                   | push                ecx
            //   6a00                 | push                0
            //   6a10                 | push                0x10

        $sequence_6 = { 83e10f c1e102 0fb655ea 81e2c0000000 c1fa06 }
            // n = 5, score = 200
            //   83e10f               | and                 ecx, 0xf
            //   c1e102               | shl                 ecx, 2
            //   0fb655ea             | movzx               edx, byte ptr [ebp - 0x16]
            //   81e2c0000000         | and                 edx, 0xc0
            //   c1fa06               | sar                 edx, 6

        $sequence_7 = { 6a00 6a02 6800000040 8d8df0feffff 51 }
            // n = 5, score = 200
            //   6a00                 | push                0
            //   6a02                 | push                2
            //   6800000040           | push                0x40000000
            //   8d8df0feffff         | lea                 ecx, [ebp - 0x110]
            //   51                   | push                ecx

        $sequence_8 = { c744240846726565 c744240c5265736f c744241075726365 c744241400000000 ff15???????? }
            // n = 5, score = 100
            //   c744240846726565     | mov                 dword ptr [esp + 8], 0x65657246
            //   c744240c5265736f     | mov                 dword ptr [esp + 0xc], 0x6f736552
            //   c744241075726365     | mov                 dword ptr [esp + 0x10], 0x65637275
            //   c744241400000000     | mov                 dword ptr [esp + 0x14], 0
            //   ff15????????         |                     

        $sequence_9 = { 8904bd70584000 8b4c2448 5e 5b }
            // n = 4, score = 100
            //   8904bd70584000       | mov                 dword ptr [edi*4 + 0x405870], eax
            //   8b4c2448             | mov                 ecx, dword ptr [esp + 0x48]
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx

        $sequence_10 = { e8???????? 83c418 85c0 7662 50 }
            // n = 5, score = 100
            //   e8????????           |                     
            //   83c418               | add                 esp, 0x18
            //   85c0                 | test                eax, eax
            //   7662                 | jbe                 0x64
            //   50                   | push                eax

        $sequence_11 = { ff15???????? 8b442414 6683f809 7505 bd02000000 5b e8???????? }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   8b442414             | mov                 eax, dword ptr [esp + 0x14]
            //   6683f809             | cmp                 ax, 9
            //   7505                 | jne                 7
            //   bd02000000           | mov                 ebp, 2
            //   5b                   | pop                 ebx
            //   e8????????           |                     

        $sequence_12 = { 7537 3905???????? 7509 57 }
            // n = 4, score = 100
            //   7537                 | jne                 0x39
            //   3905????????         |                     
            //   7509                 | jne                 0xb
            //   57                   | push                edi

        $sequence_13 = { 8975fc 3bc6 0f84f0010000 3bde 0f84e8010000 397570 0f84df010000 }
            // n = 7, score = 100
            //   8975fc               | mov                 dword ptr [ebp - 4], esi
            //   3bc6                 | cmp                 eax, esi
            //   0f84f0010000         | je                  0x1f6
            //   3bde                 | cmp                 ebx, esi
            //   0f84e8010000         | je                  0x1ee
            //   397570               | cmp                 dword ptr [ebp + 0x70], esi
            //   0f84df010000         | je                  0x1e5

        $sequence_14 = { 89551c c6452000 6a3f 6a00 }
            // n = 4, score = 100
            //   89551c               | mov                 dword ptr [ebp + 0x1c], edx
            //   c6452000             | mov                 byte ptr [ebp + 0x20], 0
            //   6a3f                 | push                0x3f
            //   6a00                 | push                0

        $sequence_15 = { 51 8d561a 52 c64619b8 e8???????? 83c448 c6461eff }
            // n = 7, score = 100
            //   51                   | push                ecx
            //   8d561a               | lea                 edx, [esi + 0x1a]
            //   52                   | push                edx
            //   c64619b8             | mov                 byte ptr [esi + 0x19], 0xb8
            //   e8????????           |                     
            //   83c448               | add                 esp, 0x48
            //   c6461eff             | mov                 byte ptr [esi + 0x1e], 0xff

    condition:
        7 of them and filesize < 303104
}