rule win_bs2005_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.bs2005."
        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.bs2005"
        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 = { 8d9334010000 8bf0 8bff 8a08 40 }
            // n = 5, score = 100
            //   8d9334010000         | lea                 edx, [ebx + 0x134]
            //   8bf0                 | mov                 esi, eax
            //   8bff                 | mov                 edi, edi
            //   8a08                 | mov                 cl, byte ptr [eax]
            //   40                   | inc                 eax

        $sequence_1 = { 51 8d5705 52 83c020 50 e8???????? }
            // n = 6, score = 100
            //   51                   | push                ecx
            //   8d5705               | lea                 edx, [edi + 5]
            //   52                   | push                edx
            //   83c020               | add                 eax, 0x20
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_2 = { eb02 33f6 c745fcffffffff 8b1d???????? 897704 833e00 0f8594000000 }
            // n = 7, score = 100
            //   eb02                 | jmp                 4
            //   33f6                 | xor                 esi, esi
            //   c745fcffffffff       | mov                 dword ptr [ebp - 4], 0xffffffff
            //   8b1d????????         |                     
            //   897704               | mov                 dword ptr [edi + 4], esi
            //   833e00               | cmp                 dword ptr [esi], 0
            //   0f8594000000         | jne                 0x9a

        $sequence_3 = { 83c404 8bf8 6800040000 897dfc }
            // n = 4, score = 100
            //   83c404               | add                 esp, 4
            //   8bf8                 | mov                 edi, eax
            //   6800040000           | push                0x400
            //   897dfc               | mov                 dword ptr [ebp - 4], edi

        $sequence_4 = { 8be5 5d c3 85c0 0f8516040000 8b45f4 50 }
            // n = 7, score = 100
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   85c0                 | test                eax, eax
            //   0f8516040000         | jne                 0x41c
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   50                   | push                eax

        $sequence_5 = { 8b0e 83c404 69c0e8030000 89814c000400 }
            // n = 4, score = 100
            //   8b0e                 | mov                 ecx, dword ptr [esi]
            //   83c404               | add                 esp, 4
            //   69c0e8030000         | imul                eax, eax, 0x3e8
            //   89814c000400         | mov                 dword ptr [ecx + 0x4004c], eax

        $sequence_6 = { 50 8bd9 8bf2 89bdb8feffff }
            // n = 4, score = 100
            //   50                   | push                eax
            //   8bd9                 | mov                 ebx, ecx
            //   8bf2                 | mov                 esi, edx
            //   89bdb8feffff         | mov                 dword ptr [ebp - 0x148], edi

        $sequence_7 = { 2bc6 40 50 51 52 }
            // n = 5, score = 100
            //   2bc6                 | sub                 eax, esi
            //   40                   | inc                 eax
            //   50                   | push                eax
            //   51                   | push                ecx
            //   52                   | push                edx

        $sequence_8 = { 88543bff 83ff20 7ce6 8b55e0 8b45fc 83c2e0 }
            // n = 6, score = 100
            //   88543bff             | mov                 byte ptr [ebx + edi - 1], dl
            //   83ff20               | cmp                 edi, 0x20
            //   7ce6                 | jl                  0xffffffe8
            //   8b55e0               | mov                 edx, dword ptr [ebp - 0x20]
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   83c2e0               | add                 edx, -0x20

        $sequence_9 = { 8a8149000400 8b9754060000 888211010000 8b8754060000 83c40c 8bf7 }
            // n = 6, score = 100
            //   8a8149000400         | mov                 al, byte ptr [ecx + 0x40049]
            //   8b9754060000         | mov                 edx, dword ptr [edi + 0x654]
            //   888211010000         | mov                 byte ptr [edx + 0x111], al
            //   8b8754060000         | mov                 eax, dword ptr [edi + 0x654]
            //   83c40c               | add                 esp, 0xc
            //   8bf7                 | mov                 esi, edi

    condition:
        7 of them and filesize < 212992
}

import "pe"

rule win_bs2005_w0 {
    meta:
        description = "Detects malware from APT 15 report by NCC Group"
        author = "Florian Roth"
        reference = "https://goo.gl/HZ5XMN"
        date = "2018-03-10"
        hash = "750d9eecd533f89b8aa13aeab173a1cf813b021b6824bc30e60f5db6fa7b950b"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.bs2005"
        malpedia_version = "20180312"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $x1 = "AAAAKQAASCMAABi+AABnhEBj8vep7VRoAEPRWLweGc0/eiDrXGajJXRxbXsTXAcZAABK4QAAPWwAACzWAAByrg==" fullword ascii
        $x2 = "AAAAKQAASCMAABi+AABnhKv3kXJJousn5YzkjGF46eE3G8ZGse4B9uoqJo8Q2oF0AABK4QAAPWwAACzWAAByrg==" fullword ascii

        $a1 = "http://%s/content.html?id=%s" fullword ascii
        $a2 = "http://%s/main.php?ssid=%s" fullword ascii
        $a3 = "http://%s/webmail.php?id=%s" fullword ascii
        $a9 = "http://%s/error.html?tab=%s" fullword ascii

        $s1 = "%s\\~tmp.txt" fullword ascii
        $s2 = "%s /C %s >>\"%s\" 2>&1" fullword ascii
        $s3 = "DisableFirstRunCustomize" fullword ascii
    condition:
        1 of ($x*) or 2 of them
}