rule win_ramnit_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.ramnit."
        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.ramnit"
        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 = { 8945fc ff7508 e8???????? ff75fc ff7508 e8???????? }
            // n = 6, score = 4000
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     

        $sequence_1 = { e8???????? 8b45fc 8b16 83c204 5e 5f 59 }
            // n = 7, score = 4000
            //   e8????????           |                     
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   8b16                 | mov                 edx, dword ptr [esi]
            //   83c204               | add                 edx, 4
            //   5e                   | pop                 esi
            //   5f                   | pop                 edi
            //   59                   | pop                 ecx

        $sequence_2 = { 5e 8a9c0501ffffff 881f 8ac3 50 52 ff7518 }
            // n = 7, score = 4000
            //   5e                   | pop                 esi
            //   8a9c0501ffffff       | mov                 bl, byte ptr [ebp + eax - 0xff]
            //   881f                 | mov                 byte ptr [edi], bl
            //   8ac3                 | mov                 al, bl
            //   50                   | push                eax
            //   52                   | push                edx
            //   ff7518               | push                dword ptr [ebp + 0x18]

        $sequence_3 = { 8a9c0501ffffff 881f 8ac3 50 52 ff7518 }
            // n = 6, score = 4000
            //   8a9c0501ffffff       | mov                 bl, byte ptr [ebp + eax - 0xff]
            //   881f                 | mov                 byte ptr [edi], bl
            //   8ac3                 | mov                 al, bl
            //   50                   | push                eax
            //   52                   | push                edx
            //   ff7518               | push                dword ptr [ebp + 0x18]

        $sequence_4 = { 8a06 50 e8???????? 38d8 751a 47 46 }
            // n = 7, score = 4000
            //   8a06                 | mov                 al, byte ptr [esi]
            //   50                   | push                eax
            //   e8????????           |                     
            //   38d8                 | cmp                 al, bl
            //   751a                 | jne                 0x1c
            //   47                   | inc                 edi
            //   46                   | inc                 esi

        $sequence_5 = { 5e 5f 59 5a }
            // n = 4, score = 4000
            //   5e                   | pop                 esi
            //   5f                   | pop                 edi
            //   59                   | pop                 ecx
            //   5a                   | pop                 edx

        $sequence_6 = { 8b36 8906 eb14 837d1400 740e }
            // n = 5, score = 4000
            //   8b36                 | mov                 esi, dword ptr [esi]
            //   8906                 | mov                 dword ptr [esi], eax
            //   eb14                 | jmp                 0x16
            //   837d1400             | cmp                 dword ptr [ebp + 0x14], 0
            //   740e                 | je                  0x10

        $sequence_7 = { b02d 8807 47 6a0a 57 e8???????? 83c70a }
            // n = 7, score = 4000
            //   b02d                 | mov                 al, 0x2d
            //   8807                 | mov                 byte ptr [edi], al
            //   47                   | inc                 edi
            //   6a0a                 | push                0xa
            //   57                   | push                edi
            //   e8????????           |                     
            //   83c70a               | add                 edi, 0xa

        $sequence_8 = { c9 c20800 55 8bec 52 53 8b5508 }
            // n = 7, score = 4000
            //   c9                   | leave               
            //   c20800               | ret                 8
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   52                   | push                edx
            //   53                   | push                ebx
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]

        $sequence_9 = { 6a08 ff35???????? e8???????? 83f800 743e }
            // n = 5, score = 4000
            //   6a08                 | push                8
            //   ff35????????         |                     
            //   e8????????           |                     
            //   83f800               | cmp                 eax, 0
            //   743e                 | je                  0x40

    condition:
        7 of them and filesize < 470016
}

rule win_ramnit_w0 {
    meta:
        author = "@VK_Intel"
        description = "Detects Ramnit banking malware VNC module"
        reference = "http://www.vkremez.com/2018/02/deeper-dive-into-ramnit-banker-vnc-ifsb.html"
        hash = "888b2c614567fb5b4474ddeeb453f8cd9f44d72efb325f7e3652fd0f748c08f1"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.ramnit"
        malpedia_version = "20180226"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $s0 = "Failed mapping a section to the target process, status 0x%x" fullword ascii
        $s1 = "Unable to map the section into the target process, error %u" fullword ascii
        $s2 = "Unable to resolve target process import, error %u" fullword ascii
        $s3 = "No module found for the target process (%u) architecture" fullword ascii
        $s4 = "A section of %u bytes mapped to the target process at 0x%p" fullword ascii
        $s5 = "CreateProcessAsUserA %s->%s failed" fullword ascii
        $s6 = "Dep PsSupGetProcessModules, ModCount = %d " fullword ascii
        $s7 = "ActiveDll: PatchProcessMemory failed, error: %u" fullword ascii
        $s8 = "CreateProcessAsUserW %S->%S failed" fullword ascii
        $s9 = "AcInjectDll: GetOEP failed, error: %u" fullword ascii
        $s10 = "Shared section mapped at 0x%p. Starting within VNC session process." fullword ascii
        $s11 = "CreateToolhelp32Snapshot (of processes) failed err=%lu" fullword ascii
    condition:
        all of them
}