rule win_grok_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.grok."
        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.grok"
        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 = { 6a0d 6a01 8d450b 50 }
            // n = 4, score = 400
            //   6a0d                 | push                0xd
            //   6a01                 | push                1
            //   8d450b               | lea                 eax, [ebp + 0xb]
            //   50                   | push                eax

        $sequence_1 = { 3bc7 8b3d???????? 7403 50 ffd7 56 ffd7 }
            // n = 7, score = 400
            //   3bc7                 | cmp                 eax, edi
            //   8b3d????????         |                     
            //   7403                 | je                  5
            //   50                   | push                eax
            //   ffd7                 | call                edi
            //   56                   | push                esi
            //   ffd7                 | call                edi

        $sequence_2 = { 7404 3ccb 7593 33c0 5f 5e 5b }
            // n = 7, score = 400
            //   7404                 | je                  6
            //   3ccb                 | cmp                 al, 0xcb
            //   7593                 | jne                 0xffffff95
            //   33c0                 | xor                 eax, eax
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx

        $sequence_3 = { ff750c 8b5dfc ff7508 e8???????? 8bd8 3bdf 7cc6 }
            // n = 7, score = 400
            //   ff750c               | push                dword ptr [ebp + 0xc]
            //   8b5dfc               | mov                 ebx, dword ptr [ebp - 4]
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     
            //   8bd8                 | mov                 ebx, eax
            //   3bdf                 | cmp                 ebx, edi
            //   7cc6                 | jl                  0xffffffc8

        $sequence_4 = { 751c be7a0000c0 a1???????? 53 ffb0c4010000 ff15???????? 8bc6 }
            // n = 7, score = 400
            //   751c                 | jne                 0x1e
            //   be7a0000c0           | mov                 esi, 0xc000007a
            //   a1????????           |                     
            //   53                   | push                ebx
            //   ffb0c4010000         | push                dword ptr [eax + 0x1c4]
            //   ff15????????         |                     
            //   8bc6                 | mov                 eax, esi

        $sequence_5 = { 51 a1???????? 8b8838010000 034844 8b903c010000 53 56 }
            // n = 7, score = 400
            //   51                   | push                ecx
            //   a1????????           |                     
            //   8b8838010000         | mov                 ecx, dword ptr [eax + 0x138]
            //   034844               | add                 ecx, dword ptr [eax + 0x44]
            //   8b903c010000         | mov                 edx, dword ptr [eax + 0x13c]
            //   53                   | push                ebx
            //   56                   | push                esi

        $sequence_6 = { 85c0 894618 0f849c000000 68???????? 8d45ec 50 ffd7 }
            // n = 7, score = 400
            //   85c0                 | test                eax, eax
            //   894618               | mov                 dword ptr [esi + 0x18], eax
            //   0f849c000000         | je                  0xa2
            //   68????????           |                     
            //   8d45ec               | lea                 eax, [ebp - 0x14]
            //   50                   | push                eax
            //   ffd7                 | call                edi

        $sequence_7 = { 8975e0 3bf3 750e c745e4010000c0 eb35 }
            // n = 5, score = 400
            //   8975e0               | mov                 dword ptr [ebp - 0x20], esi
            //   3bf3                 | cmp                 esi, ebx
            //   750e                 | jne                 0x10
            //   c745e4010000c0       | mov                 dword ptr [ebp - 0x1c], 0xc0000001
            //   eb35                 | jmp                 0x37

        $sequence_8 = { 50 ff7510 8975f0 ff750c 8975ec 668975d4 668975d6 }
            // n = 7, score = 400
            //   50                   | push                eax
            //   ff7510               | push                dword ptr [ebp + 0x10]
            //   8975f0               | mov                 dword ptr [ebp - 0x10], esi
            //   ff750c               | push                dword ptr [ebp + 0xc]
            //   8975ec               | mov                 dword ptr [ebp - 0x14], esi
            //   668975d4             | mov                 word ptr [ebp - 0x2c], si
            //   668975d6             | mov                 word ptr [ebp - 0x2a], si

        $sequence_9 = { 83ec10 837d0800 57 0f8480000000 837d0c00 747a }
            // n = 6, score = 400
            //   83ec10               | sub                 esp, 0x10
            //   837d0800             | cmp                 dword ptr [ebp + 8], 0
            //   57                   | push                edi
            //   0f8480000000         | je                  0x86
            //   837d0c00             | cmp                 dword ptr [ebp + 0xc], 0
            //   747a                 | je                  0x7c

    condition:
        7 of them and filesize < 84992
}

rule win_grok_w0 {
	meta:
	    author = "Kaspersky Lab"
	    copyright = "Kaspersky Lab"
	    description = "Rule to detect the crypto library used in Equation group malware"
	    version = "1.0"
	    last_modified = "2015-02-16"
	    reference = "https://securelist.com/blog/"
	    source = "https://github.com/mattulm/sfiles_yara/blob/master/malware/Equation.yar"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.grok"
        malpedia_version = "20170517"
        malpedia_sharing = "TLP:WHITE"
        malpedia_license = ""
	strings:
	    $a={37 DF E8 B6 C7 9C 0B AE 91 EF F0 3B 90 C6 80 85 5D 19 4B 45 44 12 3C E2 0D 5C 1C 7B C4 FF D6 05 17 14 4F 03 74 1E 41 DA 8F 7D DE 7E 99 F1 35 AC B8 46 93 CE 23 82 07 EB 2B D4 72 71 40 F3 B0 F7 78 D7 4C D1 55 1A 39 83 18 FA E1 9A 56 B1 96 AB A6 30 C5 5F BE 0C 50 C1}
	condition:
	    $a
}