rule win_bs2005_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        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 = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { ff15???????? 85c0 8b8564ffffff 7836 85c0 }
            // n = 5, score = 100
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   8b8564ffffff         | mov                 eax, dword ptr [ebp - 0x9c]
            //   7836                 | js                  0x38
            //   85c0                 | test                eax, eax

        $sequence_1 = { 52 50 8b4124 ffd0 85c0 7848 8b45e4 }
            // n = 7, score = 100
            //   52                   | push                edx
            //   50                   | push                eax
            //   8b4124               | mov                 eax, dword ptr [ecx + 0x24]
            //   ffd0                 | call                eax
            //   85c0                 | test                eax, eax
            //   7848                 | js                  0x4a
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]

        $sequence_2 = { e8???????? 84c0 0f8473ffffff 8d9644050000 b904010000 8bc2 c60000 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   84c0                 | test                al, al
            //   0f8473ffffff         | je                  0xffffff79
            //   8d9644050000         | lea                 edx, [esi + 0x544]
            //   b904010000           | mov                 ecx, 0x104
            //   8bc2                 | mov                 eax, edx
            //   c60000               | mov                 byte ptr [eax], 0

        $sequence_3 = { 8945f4 894dfc 8955f0 8b45f8 }
            // n = 4, score = 100
            //   8945f4               | mov                 dword ptr [ebp - 0xc], eax
            //   894dfc               | mov                 dword ptr [ebp - 4], ecx
            //   8955f0               | mov                 dword ptr [ebp - 0x10], edx
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]

        $sequence_4 = { 8bf8 6800040000 897dfc e8???????? 83c404 }
            // n = 5, score = 100
            //   8bf8                 | mov                 edi, eax
            //   6800040000           | push                0x400
            //   897dfc               | mov                 dword ptr [ebp - 4], edi
            //   e8????????           |                     
            //   83c404               | add                 esp, 4

        $sequence_5 = { ffd6 8b45e8 50 ffd7 8d4ddc }
            // n = 5, score = 100
            //   ffd6                 | call                esi
            //   8b45e8               | mov                 eax, dword ptr [ebp - 0x18]
            //   50                   | push                eax
            //   ffd7                 | call                edi
            //   8d4ddc               | lea                 ecx, [ebp - 0x24]

        $sequence_6 = { 50 8d45bc 50 8d4710 50 6a00 6a01 }
            // n = 7, score = 100
            //   50                   | push                eax
            //   8d45bc               | lea                 eax, [ebp - 0x44]
            //   50                   | push                eax
            //   8d4710               | lea                 eax, [edi + 0x10]
            //   50                   | push                eax
            //   6a00                 | push                0
            //   6a01                 | push                1

        $sequence_7 = { be???????? 8d7db8 f3a5 8bc2 c1e802 83e03f }
            // n = 6, score = 100
            //   be????????           |                     
            //   8d7db8               | lea                 edi, [ebp - 0x48]
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   8bc2                 | mov                 eax, edx
            //   c1e802               | shr                 eax, 2
            //   83e03f               | and                 eax, 0x3f

        $sequence_8 = { b904010000 8d4310 c60000 40 49 75f9 b904010000 }
            // n = 7, score = 100
            //   b904010000           | mov                 ecx, 0x104
            //   8d4310               | lea                 eax, [ebx + 0x10]
            //   c60000               | mov                 byte ptr [eax], 0
            //   40                   | inc                 eax
            //   49                   | dec                 ecx
            //   75f9                 | jne                 0xfffffffb
            //   b904010000           | mov                 ecx, 0x104

        $sequence_9 = { 8b85c4feffff 3bc3 7403 50 ffd6 8b85d0feffff 3bc3 }
            // n = 7, score = 100
            //   8b85c4feffff         | mov                 eax, dword ptr [ebp - 0x13c]
            //   3bc3                 | cmp                 eax, ebx
            //   7403                 | je                  5
            //   50                   | push                eax
            //   ffd6                 | call                esi
            //   8b85d0feffff         | mov                 eax, dword ptr [ebp - 0x130]
            //   3bc3                 | cmp                 eax, ebx

    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
}