rule win_fatal_rat_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        version = "1"
        description = "Detects win.fatal_rat."
        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.fatal_rat"
        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 = { 3bd1 894e7c 899684000000 888e80000000 894e78 898e90000000 894e74 }
            // n = 7, score = 100
            //   3bd1                 | cmp                 edx, ecx
            //   894e7c               | mov                 dword ptr [esi + 0x7c], ecx
            //   899684000000         | mov                 dword ptr [esi + 0x84], edx
            //   888e80000000         | mov                 byte ptr [esi + 0x80], cl
            //   894e78               | mov                 dword ptr [esi + 0x78], ecx
            //   898e90000000         | mov                 dword ptr [esi + 0x90], ecx
            //   894e74               | mov                 dword ptr [esi + 0x74], ecx

        $sequence_1 = { 6a28 ff15???????? 50 ff55f0 85c0 746f 8b450c }
            // n = 7, score = 100
            //   6a28                 | push                0x28
            //   ff15????????         |                     
            //   50                   | push                eax
            //   ff55f0               | call                dword ptr [ebp - 0x10]
            //   85c0                 | test                eax, eax
            //   746f                 | je                  0x71
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]

        $sequence_2 = { 56 33db 57 53 ff15???????? 6a3b 33c0 }
            // n = 7, score = 100
            //   56                   | push                esi
            //   33db                 | xor                 ebx, ebx
            //   57                   | push                edi
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   6a3b                 | push                0x3b
            //   33c0                 | xor                 eax, eax

        $sequence_3 = { ff248d0fdd0010 3d02010000 0f8291000000 837df80a 0f8287000000 8b450c }
            // n = 6, score = 100
            //   ff248d0fdd0010       | jmp                 dword ptr [ecx*4 + 0x1000dd0f]
            //   3d02010000           | cmp                 eax, 0x102
            //   0f8291000000         | jb                  0x97
            //   837df80a             | cmp                 dword ptr [ebp - 8], 0xa
            //   0f8287000000         | jb                  0x8d
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]

        $sequence_4 = { 8d85fcfeffff 57 50 ff15???????? 8d85fcfeffff 50 e8???????? }
            // n = 7, score = 100
            //   8d85fcfeffff         | lea                 eax, [ebp - 0x104]
            //   57                   | push                edi
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8d85fcfeffff         | lea                 eax, [ebp - 0x104]
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_5 = { e8???????? 85c0 59 7426 57 8d45e4 }
            // n = 6, score = 100
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   59                   | pop                 ecx
            //   7426                 | je                  0x28
            //   57                   | push                edi
            //   8d45e4               | lea                 eax, [ebp - 0x1c]

        $sequence_6 = { 7409 ff7508 e8???????? 59 8325????????00 33c0 5d }
            // n = 7, score = 100
            //   7409                 | je                  0xb
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   8325????????00       |                     
            //   33c0                 | xor                 eax, eax
            //   5d                   | pop                 ebp

        $sequence_7 = { 85c0 59 7426 57 8d4594 53 }
            // n = 6, score = 100
            //   85c0                 | test                eax, eax
            //   59                   | pop                 ecx
            //   7426                 | je                  0x28
            //   57                   | push                edi
            //   8d4594               | lea                 eax, [ebp - 0x6c]
            //   53                   | push                ebx

        $sequence_8 = { 8d85f0feffff 50 ff15???????? 50 8d85f0feffff 50 6a01 }
            // n = 7, score = 100
            //   8d85f0feffff         | lea                 eax, [ebp - 0x110]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   50                   | push                eax
            //   8d85f0feffff         | lea                 eax, [ebp - 0x110]
            //   50                   | push                eax
            //   6a01                 | push                1

        $sequence_9 = { ff75dc 8b35???????? ffd6 8945e4 68???????? ff75dc ffd6 }
            // n = 7, score = 100
            //   ff75dc               | push                dword ptr [ebp - 0x24]
            //   8b35????????         |                     
            //   ffd6                 | call                esi
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax
            //   68????????           |                     
            //   ff75dc               | push                dword ptr [ebp - 0x24]
            //   ffd6                 | call                esi

    condition:
        7 of them and filesize < 344064
}

rule win_fatal_rat_w0 {
    meta: 
        author = "AT&T Alien Labs" 
        description = "Detects FatalRAT, unpacked malware." 
        type = "malware" 
        sha256 = "ec0dcfe2d8380a4bafadb3ed73b546cbf73ef78f893e32202042a5818b67ce56" 
        reference = "https://cybersecurity.att.com/blogs/labs-research/new-sophisticated-rat-in-town-fatalrat-analysis"
        copyright = "Alienvault Inc. 2021" 
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.fatal_rat"
        malpedia_rule_date = "20210820"
        malpedia_version = "20210820"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings: 
        $decrypt_func = {EC 0F B6 45 10 99 B9 AB 05 00 00 56 F7 F9 8B 75 0C 80 C2 3D 85 F6 76 0F 8B 45 08 8A 08 32 CA 02 CA 88 08 40 4E 75 F4 5E 5D C3} 
        $s1 = "SVP7-Thread running..." 
        $s2 = "nw_elf.dll" 
    condition: 
        uint16(0) == 0x5a4d and all of them
}