rule win_krbanker_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.krbanker."
        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.krbanker"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { f3a5 59 85c9 0f842a000000 50 ad 56 }
            // n = 7, score = 400
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   59                   | pop                 ecx
            //   85c9                 | test                ecx, ecx
            //   0f842a000000         | je                  0x30
            //   50                   | push                eax
            //   ad                   | lodsd               eax, dword ptr [esi]
            //   56                   | push                esi

        $sequence_1 = { 8b6a04 8b7104 8d7a08 8b5020 }
            // n = 4, score = 400
            //   8b6a04               | mov                 ebp, dword ptr [edx + 4]
            //   8b7104               | mov                 esi, dword ptr [ecx + 4]
            //   8d7a08               | lea                 edi, [edx + 8]
            //   8b5020               | mov                 edx, dword ptr [eax + 0x20]

        $sequence_2 = { 0f8dd6000000 8b44244c 85c0 0f84ca000000 53 }
            // n = 5, score = 400
            //   0f8dd6000000         | jge                 0xdc
            //   8b44244c             | mov                 eax, dword ptr [esp + 0x4c]
            //   85c0                 | test                eax, eax
            //   0f84ca000000         | je                  0xd0
            //   53                   | push                ebx

        $sequence_3 = { 5e 5b c3 d9442410 e8???????? 8ad8 5e }
            // n = 7, score = 400
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx
            //   c3                   | ret                 
            //   d9442410             | fld                 dword ptr [esp + 0x10]
            //   e8????????           |                     
            //   8ad8                 | mov                 bl, al
            //   5e                   | pop                 esi

        $sequence_4 = { 8945c0 ff75c0 ff75c4 ff75c8 ff75cc }
            // n = 5, score = 400
            //   8945c0               | mov                 dword ptr [ebp - 0x40], eax
            //   ff75c0               | push                dword ptr [ebp - 0x40]
            //   ff75c4               | push                dword ptr [ebp - 0x3c]
            //   ff75c8               | push                dword ptr [ebp - 0x38]
            //   ff75cc               | push                dword ptr [ebp - 0x34]

        $sequence_5 = { 6874000000 6801000000 bb40010000 e8???????? 83c410 8945d0 6801010080 }
            // n = 7, score = 400
            //   6874000000           | push                0x74
            //   6801000000           | push                1
            //   bb40010000           | mov                 ebx, 0x140
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   8945d0               | mov                 dword ptr [ebp - 0x30], eax
            //   6801010080           | push                0x80000101

        $sequence_6 = { 8b442410 2bf3 03fb 8bde 8a08 }
            // n = 5, score = 400
            //   8b442410             | mov                 eax, dword ptr [esp + 0x10]
            //   2bf3                 | sub                 esi, ebx
            //   03fb                 | add                 edi, ebx
            //   8bde                 | mov                 ebx, esi
            //   8a08                 | mov                 cl, byte ptr [eax]

        $sequence_7 = { 83ec28 8b44243c 53 55 56 8b500c 8b08 }
            // n = 7, score = 400
            //   83ec28               | sub                 esp, 0x28
            //   8b44243c             | mov                 eax, dword ptr [esp + 0x3c]
            //   53                   | push                ebx
            //   55                   | push                ebp
            //   56                   | push                esi
            //   8b500c               | mov                 edx, dword ptr [eax + 0xc]
            //   8b08                 | mov                 ecx, dword ptr [eax]

        $sequence_8 = { b8???????? eb11 81f905000080 7509 85c0 }
            // n = 5, score = 400
            //   b8????????           |                     
            //   eb11                 | jmp                 0x13
            //   81f905000080         | cmp                 ecx, 0x80000005
            //   7509                 | jne                 0xb
            //   85c0                 | test                eax, eax

        $sequence_9 = { 8b5df8 668903 8b5dfc 83c308 895df8 }
            // n = 5, score = 400
            //   8b5df8               | mov                 ebx, dword ptr [ebp - 8]
            //   668903               | mov                 word ptr [ebx], ax
            //   8b5dfc               | mov                 ebx, dword ptr [ebp - 4]
            //   83c308               | add                 ebx, 8
            //   895df8               | mov                 dword ptr [ebp - 8], ebx

    condition:
        7 of them and filesize < 1826816
}

rule win_krbanker_w0 {
    meta:
        author = "Proofpoint Staff"
        info = "krbanker / blackmoon update"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.krbanker"
        malpedia_version = "20170410"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
            $s1 = "BlackMoon RunTime Error:" nocase wide ascii
            $s2 = "\\system32\\rundll32.exe" wide ascii
            $s3 = "cmd.exe /c ipconfig /flushdns" wide ascii
            $s4 = "\\system32\\drivers\\etc\\hosts.ics" wide ascii

    condition:
            all of them
}