rule win_metastealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.metastealer."
        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.metastealer"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { f30f1005???????? f30f1145cc f30f1005???????? eb2f f30f1005???????? f30f1145c4 f30f1005???????? }
            // n = 7, score = 200
            //   f30f1005????????     |                     
            //   f30f1145cc           | movss               dword ptr [ebp - 0x34], xmm0
            //   f30f1005????????     |                     
            //   eb2f                 | jmp                 0x31
            //   f30f1005????????     |                     
            //   f30f1145c4           | movss               dword ptr [ebp - 0x3c], xmm0
            //   f30f1005????????     |                     

        $sequence_1 = { f30f7ec8 0f57c0 660f61c8 f30fe6c1 660f73d908 660f59c2 660f58c3 }
            // n = 7, score = 200
            //   f30f7ec8             | movq                xmm1, xmm0
            //   0f57c0               | xorps               xmm0, xmm0
            //   660f61c8             | punpcklwd           xmm1, xmm0
            //   f30fe6c1             | cvtdq2pd            xmm0, xmm1
            //   660f73d908           | psrldq              xmm1, 8
            //   660f59c2             | mulpd               xmm0, xmm2
            //   660f58c3             | addpd               xmm0, xmm3

        $sequence_2 = { ffd0 3b4510 7559 85d2 7555 90 85f6 }
            // n = 7, score = 200
            //   ffd0                 | call                eax
            //   3b4510               | cmp                 eax, dword ptr [ebp + 0x10]
            //   7559                 | jne                 0x5b
            //   85d2                 | test                edx, edx
            //   7555                 | jne                 0x57
            //   90                   | nop                 
            //   85f6                 | test                esi, esi

        $sequence_3 = { ff510c 8bf0 85f6 0f850e010000 895dfc 8b45f8 8d55e8 }
            // n = 7, score = 200
            //   ff510c               | call                dword ptr [ecx + 0xc]
            //   8bf0                 | mov                 esi, eax
            //   85f6                 | test                esi, esi
            //   0f850e010000         | jne                 0x114
            //   895dfc               | mov                 dword ptr [ebp - 4], ebx
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]
            //   8d55e8               | lea                 edx, [ebp - 0x18]

        $sequence_4 = { f7e2 03c1 8b4df8 83d200 8955fc 8b5710 23d0 }
            // n = 7, score = 200
            //   f7e2                 | mul                 edx
            //   03c1                 | add                 eax, ecx
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   83d200               | adc                 edx, 0
            //   8955fc               | mov                 dword ptr [ebp - 4], edx
            //   8b5710               | mov                 edx, dword ptr [edi + 0x10]
            //   23d0                 | and                 edx, eax

        $sequence_5 = { eb29 85ff 7825 33c0 894508 0f1f8000000000 99 }
            // n = 7, score = 200
            //   eb29                 | jmp                 0x2b
            //   85ff                 | test                edi, edi
            //   7825                 | js                  0x27
            //   33c0                 | xor                 eax, eax
            //   894508               | mov                 dword ptr [ebp + 8], eax
            //   0f1f8000000000       | nop                 dword ptr [eax]
            //   99                   | cdq                 

        $sequence_6 = { e8???????? 0bc2 7410 c745f801000000 c745fc00000000 eb08 0f57c0 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   0bc2                 | or                  eax, edx
            //   7410                 | je                  0x12
            //   c745f801000000       | mov                 dword ptr [ebp - 8], 1
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0
            //   eb08                 | jmp                 0xa
            //   0f57c0               | xorps               xmm0, xmm0

        $sequence_7 = { c20800 55 8bec 56 57 8bf9 8d4f70 }
            // n = 7, score = 200
            //   c20800               | ret                 8
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   56                   | push                esi
            //   57                   | push                edi
            //   8bf9                 | mov                 edi, ecx
            //   8d4f70               | lea                 ecx, [edi + 0x70]

        $sequence_8 = { eb17 50 51 e8???????? 83c410 895dec 56 }
            // n = 7, score = 200
            //   eb17                 | jmp                 0x19
            //   50                   | push                eax
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   895dec               | mov                 dword ptr [ebp - 0x14], ebx
            //   56                   | push                esi

        $sequence_9 = { f20f110424 50 8d45a0 50 e8???????? 83c410 c645fc00 }
            // n = 7, score = 200
            //   f20f110424           | movsd               qword ptr [esp], xmm0
            //   50                   | push                eax
            //   8d45a0               | lea                 eax, [ebp - 0x60]
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   c645fc00             | mov                 byte ptr [ebp - 4], 0

    condition:
        7 of them and filesize < 26230784
}

rule win_metastealer_w0 {
    meta:
        description = "MetaStealer Memory"
        author = "Peter Gurney"
        date = "2022-04-29"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.metastealer"
        malpedia_rule_date = "20230119"
        malpedia_hash = ""
        malpedia_version = "20230131"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $str_c2_parse = {B8 56 55 55 55 F7 6D C4 8B C2 C1 E8 1F 03 C2 8B 55 C0 8D 04 40 2B 45 C4}
        $str_filename = ".xyz -newname hyper-v.exe" fullword wide
        $str_stackstring = {FF FF FF C7 85 ?? ?? ?? ?? ?? ?? ?? ?? C7 85 ?? ?? ?? ?? ?? ?? ?? ?? C7 85 ?? ?? ?? ?? ?? ?? ?? ?? C7 85 ?? ?? ?? ?? ?? ?? ?? ?? 66 0F EF}
    condition:
        uint16(0) == 0x5a4d and
        2 of ($str_*)
}