rule win_kagent_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.kagent."
        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.kagent"
        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 = { c1f803 85c0 7e29 33f6 85c0 }
            // n = 5, score = 400
            //   c1f803               | sar                 eax, 3
            //   85c0                 | test                eax, eax
            //   7e29                 | jle                 0x2b
            //   33f6                 | xor                 esi, esi
            //   85c0                 | test                eax, eax

        $sequence_1 = { 48 5d c3 8bff 55 8bec 83ec34 }
            // n = 7, score = 400
            //   48                   | dec                 eax
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   8bff                 | mov                 edi, edi
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   83ec34               | sub                 esp, 0x34

        $sequence_2 = { f3a5 8bc8 83e103 f3a4 8dbddcfeffff 4f }
            // n = 6, score = 400
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   8bc8                 | mov                 ecx, eax
            //   83e103               | and                 ecx, 3
            //   f3a4                 | rep movsb           byte ptr es:[edi], byte ptr [esi]
            //   8dbddcfeffff         | lea                 edi, [ebp - 0x124]
            //   4f                   | dec                 edi

        $sequence_3 = { 0bc8 51 e8???????? 898388000000 c6838c00000001 }
            // n = 5, score = 400
            //   0bc8                 | or                  ecx, eax
            //   51                   | push                ecx
            //   e8????????           |                     
            //   898388000000         | mov                 dword ptr [ebx + 0x88], eax
            //   c6838c00000001       | mov                 byte ptr [ebx + 0x8c], 1

        $sequence_4 = { f7d9 0bc8 51 e8???????? 898380000000 c6838400000001 8b8380000000 }
            // n = 7, score = 400
            //   f7d9                 | neg                 ecx
            //   0bc8                 | or                  ecx, eax
            //   51                   | push                ecx
            //   e8????????           |                     
            //   898380000000         | mov                 dword ptr [ebx + 0x80], eax
            //   c6838400000001       | mov                 byte ptr [ebx + 0x84], 1
            //   8b8380000000         | mov                 eax, dword ptr [ebx + 0x80]

        $sequence_5 = { 85f6 7405 e8???????? 57 e8???????? 8b75f0 83c404 }
            // n = 7, score = 400
            //   85f6                 | test                esi, esi
            //   7405                 | je                  7
            //   e8????????           |                     
            //   57                   | push                edi
            //   e8????????           |                     
            //   8b75f0               | mov                 esi, dword ptr [ebp - 0x10]
            //   83c404               | add                 esp, 4

        $sequence_6 = { 8b7de4 41 894dd0 83f904 0f8c78ffffff c745d000000000 8b75d0 }
            // n = 7, score = 400
            //   8b7de4               | mov                 edi, dword ptr [ebp - 0x1c]
            //   41                   | inc                 ecx
            //   894dd0               | mov                 dword ptr [ebp - 0x30], ecx
            //   83f904               | cmp                 ecx, 4
            //   0f8c78ffffff         | jl                  0xffffff7e
            //   c745d000000000       | mov                 dword ptr [ebp - 0x30], 0
            //   8b75d0               | mov                 esi, dword ptr [ebp - 0x30]

        $sequence_7 = { 53 8975f0 e8???????? 8975fc 53 c703???????? }
            // n = 6, score = 400
            //   53                   | push                ebx
            //   8975f0               | mov                 dword ptr [ebp - 0x10], esi
            //   e8????????           |                     
            //   8975fc               | mov                 dword ptr [ebp - 4], esi
            //   53                   | push                ebx
            //   c703????????         |                     

        $sequence_8 = { 51 53 e8???????? 83c410 894604 8bc6 5f }
            // n = 7, score = 400
            //   51                   | push                ecx
            //   53                   | push                ebx
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   894604               | mov                 dword ptr [esi + 4], eax
            //   8bc6                 | mov                 eax, esi
            //   5f                   | pop                 edi

        $sequence_9 = { 741c b800000400 5f 5e 5b 8b8c24b8050000 }
            // n = 6, score = 400
            //   741c                 | je                  0x1e
            //   b800000400           | mov                 eax, 0x40000
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx
            //   8b8c24b8050000       | mov                 ecx, dword ptr [esp + 0x5b8]

    condition:
        7 of them and filesize < 4972544
}

rule win_kagent_w0 {
	meta:
		description = "Backdoor used by attackers in Operation Cleaver"
		reference = "http://cylance.com/assets/Cleaver/Cylance_Operation_Cleaver_Report.pdf"
		date = "2014/12/02"
		author = "Cylance Inc."
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.kagent"
        malpedia_version = "20170521"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
	strings:
		$s1 = "kill command is in last machine, going back"
		$s2 = "message data length in B64: %d Bytes"
	condition:
		all of them
}