rule win_megumin_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.megumin."
        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.megumin"
        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 = { 83ec18 c645fc2b 8bf4 8965c8 b9???????? 6a0e e8???????? }
            // n = 7, score = 200
            //   83ec18               | sub                 esp, 0x18
            //   c645fc2b             | mov                 byte ptr [ebp - 4], 0x2b
            //   8bf4                 | mov                 esi, esp
            //   8965c8               | mov                 dword ptr [ebp - 0x38], esp
            //   b9????????           |                     
            //   6a0e                 | push                0xe
            //   e8????????           |                     

        $sequence_1 = { 53 56 57 33f6 c78524f8ffff00000000 56 56 }
            // n = 7, score = 200
            //   53                   | push                ebx
            //   56                   | push                esi
            //   57                   | push                edi
            //   33f6                 | xor                 esi, esi
            //   c78524f8ffff00000000     | mov    dword ptr [ebp - 0x7dc], 0
            //   56                   | push                esi
            //   56                   | push                esi

        $sequence_2 = { 8d4dd8 e9???????? 8d4db8 e9???????? 8b542408 8d420c 8b8a2cfeffff }
            // n = 7, score = 200
            //   8d4dd8               | lea                 ecx, [ebp - 0x28]
            //   e9????????           |                     
            //   8d4db8               | lea                 ecx, [ebp - 0x48]
            //   e9????????           |                     
            //   8b542408             | mov                 edx, dword ptr [esp + 8]
            //   8d420c               | lea                 eax, [edx + 0xc]
            //   8b8a2cfeffff         | mov                 ecx, dword ptr [edx - 0x1d4]

        $sequence_3 = { 8d4dd8 c645fc01 e8???????? 83ec10 8d8dc0fdffff 68???????? e8???????? }
            // n = 7, score = 200
            //   8d4dd8               | lea                 ecx, [ebp - 0x28]
            //   c645fc01             | mov                 byte ptr [ebp - 4], 1
            //   e8????????           |                     
            //   83ec10               | sub                 esp, 0x10
            //   8d8dc0fdffff         | lea                 ecx, [ebp - 0x240]
            //   68????????           |                     
            //   e8????????           |                     

        $sequence_4 = { 8d8d70ffffff c745840f000000 c68570ffffff00 6a07 68???????? e8???????? 8d9570ffffff }
            // n = 7, score = 200
            //   8d8d70ffffff         | lea                 ecx, [ebp - 0x90]
            //   c745840f000000       | mov                 dword ptr [ebp - 0x7c], 0xf
            //   c68570ffffff00       | mov                 byte ptr [ebp - 0x90], 0
            //   6a07                 | push                7
            //   68????????           |                     
            //   e8????????           |                     
            //   8d9570ffffff         | lea                 edx, [ebp - 0x90]

        $sequence_5 = { 53 56 8bf1 57 8b4608 2500010000 7414 }
            // n = 7, score = 200
            //   53                   | push                ebx
            //   56                   | push                esi
            //   8bf1                 | mov                 esi, ecx
            //   57                   | push                edi
            //   8b4608               | mov                 eax, dword ptr [esi + 8]
            //   2500010000           | and                 eax, 0x100
            //   7414                 | je                  0x16

        $sequence_6 = { 8d8dd4fbffff 6a08 68???????? c785e4fbffff00000000 c785e8fbffff0f000000 c685d4fbffff00 e8???????? }
            // n = 7, score = 200
            //   8d8dd4fbffff         | lea                 ecx, [ebp - 0x42c]
            //   6a08                 | push                8
            //   68????????           |                     
            //   c785e4fbffff00000000     | mov    dword ptr [ebp - 0x41c], 0
            //   c785e8fbffff0f000000     | mov    dword ptr [ebp - 0x418], 0xf
            //   c685d4fbffff00       | mov                 byte ptr [ebp - 0x42c], 0
            //   e8????????           |                     

        $sequence_7 = { 0f82cc0a0000 2bc6 83c9ff 83f8ff 0f42c8 837de810 8d45d4 }
            // n = 7, score = 200
            //   0f82cc0a0000         | jb                  0xad2
            //   2bc6                 | sub                 eax, esi
            //   83c9ff               | or                  ecx, 0xffffffff
            //   83f8ff               | cmp                 eax, -1
            //   0f42c8               | cmovb               ecx, eax
            //   837de810             | cmp                 dword ptr [ebp - 0x18], 0x10
            //   8d45d4               | lea                 eax, [ebp - 0x2c]

        $sequence_8 = { 8b1f 53 56 e8???????? ff7514 ff75f0 ff75f8 }
            // n = 7, score = 200
            //   8b1f                 | mov                 ebx, dword ptr [edi]
            //   53                   | push                ebx
            //   56                   | push                esi
            //   e8????????           |                     
            //   ff7514               | push                dword ptr [ebp + 0x14]
            //   ff75f0               | push                dword ptr [ebp - 0x10]
            //   ff75f8               | push                dword ptr [ebp - 8]

        $sequence_9 = { 51 ff7668 e8???????? ff7658 8bce 66c746640000 c6467401 }
            // n = 7, score = 200
            //   51                   | push                ecx
            //   ff7668               | push                dword ptr [esi + 0x68]
            //   e8????????           |                     
            //   ff7658               | push                dword ptr [esi + 0x58]
            //   8bce                 | mov                 ecx, esi
            //   66c746640000         | mov                 word ptr [esi + 0x64], 0
            //   c6467401             | mov                 byte ptr [esi + 0x74], 1

    condition:
        7 of them and filesize < 1007616
}

rule win_megumin_w0 {
    meta:
        description = "Detecting Megumin v2"
        author = "Fumik0_"
        date = "2019-05-02"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.megumin"
        malpedia_version = "20190503"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
        
    strings:
        $s1 = "Megumin/2.0" wide ascii
        $s2 = "/cpu" wide ascii
        $s3 = "/task?hwid=" wide ascii
        $s4 = "/gate?hwid=" wide ascii
        $s5 = "/suicide" wide ascii

    condition:
        all of them
}