rule win_kagent_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        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 = "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 = { 85f6 0f858cfcffff 8b542420 8d0411 39442438 8b5378 }
            // n = 6, score = 400
            //   85f6                 | test                esi, esi
            //   0f858cfcffff         | jne                 0xfffffc92
            //   8b542420             | mov                 edx, dword ptr [esp + 0x20]
            //   8d0411               | lea                 eax, [ecx + edx]
            //   39442438             | cmp                 dword ptr [esp + 0x38], eax
            //   8b5378               | mov                 edx, dword ptr [ebx + 0x78]

        $sequence_1 = { 7604 2bf9 eb02 33ff 8b4314 8b742418 }
            // n = 6, score = 400
            //   7604                 | jbe                 6
            //   2bf9                 | sub                 edi, ecx
            //   eb02                 | jmp                 4
            //   33ff                 | xor                 edi, edi
            //   8b4314               | mov                 eax, dword ptr [ebx + 0x14]
            //   8b742418             | mov                 esi, dword ptr [esp + 0x18]

        $sequence_2 = { 51 e8???????? 33c9 a3???????? c605????????01 c705????????00000000 }
            // n = 6, score = 400
            //   51                   | push                ecx
            //   e8????????           |                     
            //   33c9                 | xor                 ecx, ecx
            //   a3????????           |                     
            //   c605????????01       |                     
            //   c705????????00000000     |     

        $sequence_3 = { 83c8ff 5b 8be5 5d c3 66833b2d }
            // n = 6, score = 400
            //   83c8ff               | or                  eax, 0xffffffff
            //   5b                   | pop                 ebx
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   66833b2d             | cmp                 word ptr [ebx], 0x2d

        $sequence_4 = { 8bf8 83c40c 897d98 85ff }
            // n = 4, score = 400
            //   8bf8                 | mov                 edi, eax
            //   83c40c               | add                 esp, 0xc
            //   897d98               | mov                 dword ptr [ebp - 0x68], edi
            //   85ff                 | test                edi, edi

        $sequence_5 = { f7d9 0bc8 51 e8???????? 894304 c6430801 }
            // n = 6, score = 400
            //   f7d9                 | neg                 ecx
            //   0bc8                 | or                  ecx, eax
            //   51                   | push                ecx
            //   e8????????           |                     
            //   894304               | mov                 dword ptr [ebx + 4], eax
            //   c6430801             | mov                 byte ptr [ebx + 8], 1

        $sequence_6 = { 6683790200 7507 40 8906 3bc3 7ce7 8b3e }
            // n = 7, score = 400
            //   6683790200           | cmp                 word ptr [ecx + 2], 0
            //   7507                 | jne                 9
            //   40                   | inc                 eax
            //   8906                 | mov                 dword ptr [esi], eax
            //   3bc3                 | cmp                 eax, ebx
            //   7ce7                 | jl                  0xffffffe9
            //   8b3e                 | mov                 edi, dword ptr [esi]

        $sequence_7 = { ff15???????? 85c0 7428 8b5678 8b7d08 017e74 52 }
            // n = 7, score = 400
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7428                 | je                  0x2a
            //   8b5678               | mov                 edx, dword ptr [esi + 0x78]
            //   8b7d08               | mov                 edi, dword ptr [ebp + 8]
            //   017e74               | add                 dword ptr [esi + 0x74], edi
            //   52                   | push                edx

        $sequence_8 = { 57 53 8bce e8???????? 3bc7 7526 }
            // n = 6, score = 400
            //   57                   | push                edi
            //   53                   | push                ebx
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   3bc7                 | cmp                 eax, edi
            //   7526                 | jne                 0x28

        $sequence_9 = { c645fc21 8b430c 8b4b14 8d444003 8d0481 }
            // n = 5, score = 400
            //   c645fc21             | mov                 byte ptr [ebp - 4], 0x21
            //   8b430c               | mov                 eax, dword ptr [ebx + 0xc]
            //   8b4b14               | mov                 ecx, dword ptr [ebx + 0x14]
            //   8d444003             | lea                 eax, [eax + eax*2 + 3]
            //   8d0481               | lea                 eax, [ecx + eax*4]

    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
}