rule win_erbium_stealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.erbium_stealer."
        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.erbium_stealer"
        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 = { ffd6 8b5c2414 6a00 6a01 }
            // n = 4, score = 100
            //   ffd6                 | call                esi
            //   8b5c2414             | mov                 ebx, dword ptr [esp + 0x14]
            //   6a00                 | push                0
            //   6a01                 | push                1

        $sequence_1 = { 69d993010001 3bc7 75de 8b7dfc 81fb3b3b2aa6 }
            // n = 5, score = 100
            //   69d993010001         | imul                ebx, ecx, 0x1000193
            //   3bc7                 | cmp                 eax, edi
            //   75de                 | jne                 0xffffffe0
            //   8b7dfc               | mov                 edi, dword ptr [ebp - 4]
            //   81fb3b3b2aa6         | cmp                 ebx, 0xa62a3b3b

        $sequence_2 = { 8945f4 837df400 0f84a5000000 68???????? }
            // n = 4, score = 100
            //   8945f4               | mov                 dword ptr [ebp - 0xc], eax
            //   837df400             | cmp                 dword ptr [ebp - 0xc], 0
            //   0f84a5000000         | je                  0xab
            //   68????????           |                     

        $sequence_3 = { 8b4df4 8b55fc 035110 8955b0 8b45f4 }
            // n = 5, score = 100
            //   8b4df4               | mov                 ecx, dword ptr [ebp - 0xc]
            //   8b55fc               | mov                 edx, dword ptr [ebp - 4]
            //   035110               | add                 edx, dword ptr [ecx + 0x10]
            //   8955b0               | mov                 dword ptr [ebp - 0x50], edx
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]

        $sequence_4 = { 75f6 51 8d4c2454 40 }
            // n = 4, score = 100
            //   75f6                 | jne                 0xfffffff8
            //   51                   | push                ecx
            //   8d4c2454             | lea                 ecx, [esp + 0x54]
            //   40                   | inc                 eax

        $sequence_5 = { eb12 8b4dd4 83c101 894dd4 8b55ec 83c228 8955ec }
            // n = 7, score = 100
            //   eb12                 | jmp                 0x14
            //   8b4dd4               | mov                 ecx, dword ptr [ebp - 0x2c]
            //   83c101               | add                 ecx, 1
            //   894dd4               | mov                 dword ptr [ebp - 0x2c], ecx
            //   8b55ec               | mov                 edx, dword ptr [ebp - 0x14]
            //   83c228               | add                 edx, 0x28
            //   8955ec               | mov                 dword ptr [ebp - 0x14], edx

        $sequence_6 = { 8b45fc 0302 8b4de0 0fb711 81e2ff0f0000 03c2 8945d4 }
            // n = 7, score = 100
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   0302                 | add                 eax, dword ptr [edx]
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]
            //   0fb711               | movzx               edx, word ptr [ecx]
            //   81e2ff0f0000         | and                 edx, 0xfff
            //   03c2                 | add                 eax, edx
            //   8945d4               | mov                 dword ptr [ebp - 0x2c], eax

        $sequence_7 = { 8945dc 8b4de0 83c102 894de0 8b55dc 3b55c4 }
            // n = 6, score = 100
            //   8945dc               | mov                 dword ptr [ebp - 0x24], eax
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]
            //   83c102               | add                 ecx, 2
            //   894de0               | mov                 dword ptr [ebp - 0x20], ecx
            //   8b55dc               | mov                 edx, dword ptr [ebp - 0x24]
            //   3b55c4               | cmp                 edx, dword ptr [ebp - 0x3c]

        $sequence_8 = { 035110 8955e8 837df000 7506 8b45e8 8945f0 eb12 }
            // n = 7, score = 100
            //   035110               | add                 edx, dword ptr [ecx + 0x10]
            //   8955e8               | mov                 dword ptr [ebp - 0x18], edx
            //   837df000             | cmp                 dword ptr [ebp - 0x10], 0
            //   7506                 | jne                 8
            //   8b45e8               | mov                 eax, dword ptr [ebp - 0x18]
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   eb12                 | jmp                 0x14

        $sequence_9 = { 8b45fc 03440a60 8945b4 8b4db4 8b510c }
            // n = 5, score = 100
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   03440a60             | add                 eax, dword ptr [edx + ecx + 0x60]
            //   8945b4               | mov                 dword ptr [ebp - 0x4c], eax
            //   8b4db4               | mov                 ecx, dword ptr [ebp - 0x4c]
            //   8b510c               | mov                 edx, dword ptr [ecx + 0xc]

    condition:
        7 of them and filesize < 33792
}