rule win_ransomexx_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.ransomexx."
        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.ransomexx"
        malpedia_rule_date = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 897704 897708 8d7b38 3bfe 7439 8b4f08 3bce }
            // n = 7, score = 100
            //   897704               | mov                 dword ptr [edi + 4], esi
            //   897708               | mov                 dword ptr [edi + 8], esi
            //   8d7b38               | lea                 edi, [ebx + 0x38]
            //   3bfe                 | cmp                 edi, esi
            //   7439                 | je                  0x3b
            //   8b4f08               | mov                 ecx, dword ptr [edi + 8]
            //   3bce                 | cmp                 ecx, esi

        $sequence_1 = { 333c9db07e4200 8945fc 895508 3330 83c004 8945fc 8975dc }
            // n = 7, score = 100
            //   333c9db07e4200       | xor                 edi, dword ptr [ebx*4 + 0x427eb0]
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   895508               | mov                 dword ptr [ebp + 8], edx
            //   3330                 | xor                 esi, dword ptr [eax]
            //   83c004               | add                 eax, 4
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   8975dc               | mov                 dword ptr [ebp - 0x24], esi

        $sequence_2 = { 41 00745b41 009c5b41008a46 0323 }
            // n = 4, score = 100
            //   41                   | inc                 ecx
            //   00745b41             | add                 byte ptr [ebx + ebx*2 + 0x41], dh
            //   009c5b41008a46       | add                 byte ptr [ebx + ebx*2 + 0x468a0041], bl
            //   0323                 | add                 esp, dword ptr [ebx]

        $sequence_3 = { 338a886a4200 8b7004 3308 8b7808 33f1 894810 33fe }
            // n = 7, score = 100
            //   338a886a4200         | xor                 ecx, dword ptr [edx + 0x426a88]
            //   8b7004               | mov                 esi, dword ptr [eax + 4]
            //   3308                 | xor                 ecx, dword ptr [eax]
            //   8b7808               | mov                 edi, dword ptr [eax + 8]
            //   33f1                 | xor                 esi, ecx
            //   894810               | mov                 dword ptr [eax + 0x10], ecx
            //   33fe                 | xor                 edi, esi

        $sequence_4 = { 8d442408 e8???????? 8bf0 85f6 7525 8b4d0c 8b5508 }
            // n = 7, score = 100
            //   8d442408             | lea                 eax, [esp + 8]
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax
            //   85f6                 | test                esi, esi
            //   7525                 | jne                 0x27
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]

        $sequence_5 = { 0fb6701e 0fb6b688614200 c1e108 33ce 0fb6701d 0fb6b688614200 c1e108 }
            // n = 7, score = 100
            //   0fb6701e             | movzx               esi, byte ptr [eax + 0x1e]
            //   0fb6b688614200       | movzx               esi, byte ptr [esi + 0x426188]
            //   c1e108               | shl                 ecx, 8
            //   33ce                 | xor                 ecx, esi
            //   0fb6701d             | movzx               esi, byte ptr [eax + 0x1d]
            //   0fb6b688614200       | movzx               esi, byte ptr [esi + 0x426188]
            //   c1e108               | shl                 ecx, 8

        $sequence_6 = { 8d48bf 80f905 7706 0fbed0 83ea37 8d489f 80f905 }
            // n = 7, score = 100
            //   8d48bf               | lea                 ecx, [eax - 0x41]
            //   80f905               | cmp                 cl, 5
            //   7706                 | ja                  8
            //   0fbed0               | movsx               edx, al
            //   83ea37               | sub                 edx, 0x37
            //   8d489f               | lea                 ecx, [eax - 0x61]
            //   80f905               | cmp                 cl, 5

        $sequence_7 = { c3 8bff 55 8bec 8b4508 33c9 3b04cd60304200 }
            // n = 7, score = 100
            //   c3                   | ret                 
            //   8bff                 | mov                 edi, edi
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   33c9                 | xor                 ecx, ecx
            //   3b04cd60304200       | cmp                 eax, dword ptr [ecx*8 + 0x423060]

        $sequence_8 = { 6a00 ff15???????? 8b1d???????? 57 6a00 6a01 ffd3 }
            // n = 7, score = 100
            //   6a00                 | push                0
            //   ff15????????         |                     
            //   8b1d????????         |                     
            //   57                   | push                edi
            //   6a00                 | push                0
            //   6a01                 | push                1
            //   ffd3                 | call                ebx

        $sequence_9 = { 8b542408 f30f6f09 f30f7f0a 660f6fd1 8d0530304200 660f6f00 8d0500304200 }
            // n = 7, score = 100
            //   8b542408             | mov                 edx, dword ptr [esp + 8]
            //   f30f6f09             | movdqu              xmm1, xmmword ptr [ecx]
            //   f30f7f0a             | movdqu              xmmword ptr [edx], xmm1
            //   660f6fd1             | movdqa              xmm2, xmm1
            //   8d0530304200         | lea                 eax, [0x423030]
            //   660f6f00             | movdqa              xmm0, xmmword ptr [eax]
            //   8d0500304200         | lea                 eax, [0x423000]

    condition:
        7 of them and filesize < 372736
}