rule win_krbanker_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        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 = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 3bf2 7d02 33f6 8a4500 240c }
            // n = 5, score = 400
            //   3bf2                 | cmp                 esi, edx
            //   7d02                 | jge                 4
            //   33f6                 | xor                 esi, esi
            //   8a4500               | mov                 al, byte ptr [ebp]
            //   240c                 | and                 al, 0xc

        $sequence_1 = { e8???????? 83c404 d945d8 eb06 }
            // n = 4, score = 400
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   d945d8               | fld                 dword ptr [ebp - 0x28]
            //   eb06                 | jmp                 8

        $sequence_2 = { 895c2414 8b482c 85c9 740e 8b4824 }
            // n = 5, score = 400
            //   895c2414             | mov                 dword ptr [esp + 0x14], ebx
            //   8b482c               | mov                 ecx, dword ptr [eax + 0x2c]
            //   85c9                 | test                ecx, ecx
            //   740e                 | je                  0x10
            //   8b4824               | mov                 ecx, dword ptr [eax + 0x24]

        $sequence_3 = { 57 51 85c0 7415 50 8bd8 e8???????? }
            // n = 7, score = 400
            //   57                   | push                edi
            //   51                   | push                ecx
            //   85c0                 | test                eax, eax
            //   7415                 | je                  0x17
            //   50                   | push                eax
            //   8bd8                 | mov                 ebx, eax
            //   e8????????           |                     

        $sequence_4 = { 8b4824 33db 49 85c9 0f9cc3 }
            // n = 5, score = 400
            //   8b4824               | mov                 ecx, dword ptr [eax + 0x24]
            //   33db                 | xor                 ebx, ebx
            //   49                   | dec                 ecx
            //   85c9                 | test                ecx, ecx
            //   0f9cc3               | setl                bl

        $sequence_5 = { 8bf0 83c40c 83feff 0f848f000000 56 57 }
            // n = 6, score = 400
            //   8bf0                 | mov                 esi, eax
            //   83c40c               | add                 esp, 0xc
            //   83feff               | cmp                 esi, -1
            //   0f848f000000         | je                  0x95
            //   56                   | push                esi
            //   57                   | push                edi

        $sequence_6 = { 8b410c 3bc7 7e0a 5f 5e 5d 33c0 }
            // n = 7, score = 400
            //   8b410c               | mov                 eax, dword ptr [ecx + 0xc]
            //   3bc7                 | cmp                 eax, edi
            //   7e0a                 | jle                 0xc
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   33c0                 | xor                 eax, eax

        $sequence_7 = { e8???????? 83c404 d945e4 eb06 8955e8 dd45e4 e8???????? }
            // n = 7, score = 400
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   d945e4               | fld                 dword ptr [ebp - 0x1c]
            //   eb06                 | jmp                 8
            //   8955e8               | mov                 dword ptr [ebp - 0x18], edx
            //   dd45e4               | fld                 qword ptr [ebp - 0x1c]
            //   e8????????           |                     

        $sequence_8 = { 684b000000 6801000000 bb40010000 e8???????? 83c410 }
            // n = 5, score = 400
            //   684b000000           | push                0x4b
            //   6801000000           | push                1
            //   bb40010000           | mov                 ebx, 0x140
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10

        $sequence_9 = { 33c0 5e 83c408 c3 8b4c2420 8b542404 8d442408 }
            // n = 7, score = 400
            //   33c0                 | xor                 eax, eax
            //   5e                   | pop                 esi
            //   83c408               | add                 esp, 8
            //   c3                   | ret                 
            //   8b4c2420             | mov                 ecx, dword ptr [esp + 0x20]
            //   8b542404             | mov                 edx, dword ptr [esp + 4]
            //   8d442408             | lea                 eax, [esp + 8]

    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
}