win.daserf (Back to overview)

Daserf

aka: Muirim, Nioupale

Actor(s): Tick


There is no description at this point.

References
https://researchcenter.paloaltonetworks.com/2017/07/unit42-tick-group-continues-attacks/
http://blog.trendmicro.com/trendlabs-security-intelligence/redbaldknight-bronze-butler-daserf-backdoor-now-using-steganography/
https://www.secureworks.com/research/bronze-butler-targets-japanese-businesses
Yara Rules
[TLP:WHITE] win_daserf_auto (20190620 | autogenerated rule brought to you by yara-signator)
rule win_daserf_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2019-07-05"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator 0.2a"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.daserf"
        malpedia_version = "20190620"
        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 / approach 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 = { 51 8d442400 50 33c0 50 50 68f7844000 }
            // n = 7, score = 100
            //   51                   | push                ecx
            //   8d442400             | lea                 eax, [esp]
            //   50                   | push                eax
            //   33c0                 | xor                 eax, eax
            //   50                   | push                eax
            //   50                   | push                eax
            //   68f7844000           | push                0x4084f7

        $sequence_1 = { 0506eaec93 75?? 2dff599158 93 }
            // n = 4, score = 100
            //   0506eaec93           | add                 eax, 0x93ecea06
            //   75??                 |                     
            //   2dff599158           | sub                 eax, 0x589159ff
            //   93                   | xchg                eax, ebx

        $sequence_2 = { ffd6 8d8594fdffff 50 8d8594ecffff }
            // n = 4, score = 100
            //   ffd6                 | call                esi
            //   8d8594fdffff         | lea                 eax, [ebp - 0x26c]
            //   50                   | push                eax
            //   8d8594ecffff         | lea                 eax, [ebp - 0x136c]

        $sequence_3 = { 81c3630f0c33 2d4e8719c5 0562d2b8fd 81eba20e5718 }
            // n = 4, score = 100
            //   81c3630f0c33         | add                 ebx, 0x330c0f63
            //   2d4e8719c5           | sub                 eax, 0xc519874e
            //   0562d2b8fd           | add                 eax, 0xfdb8d262
            //   81eba20e5718         | sub                 ebx, 0x18570ea2

        $sequence_4 = { ffd6 8d45fc 6a00 50 6a01 6888e04000 53 }
            // n = 7, score = 100
            //   ffd6                 | call                esi
            //   8d45fc               | lea                 eax, [ebp - 4]
            //   6a00                 | push                0
            //   50                   | push                eax
            //   6a01                 | push                1
            //   6888e04000           | push                0x40e088
            //   53                   | push                ebx

        $sequence_5 = { 81c398f4f5f1 8bff 81eb16e1dcb1 90 2dc3d7ab86 8bf6 2d1cbd3739 }
            // n = 7, score = 100
            //   81c398f4f5f1         | add                 ebx, 0xf1f5f498
            //   8bff                 | mov                 edi, edi
            //   81eb16e1dcb1         | sub                 ebx, 0xb1dce116
            //   90                   | nop                 
            //   2dc3d7ab86           | sub                 eax, 0x86abd7c3
            //   8bf6                 | mov                 esi, esi
            //   2d1cbd3739           | sub                 eax, 0x3937bd1c

        $sequence_6 = { 055b4e8b45 81c3b0d485cc 81c3f781b4a1 81c392402699 }
            // n = 4, score = 100
            //   055b4e8b45           | add                 eax, 0x458b4e5b
            //   81c3b0d485cc         | add                 ebx, 0xcc85d4b0
            //   81c3f781b4a1         | add                 ebx, 0xa1b481f7
            //   81c392402699         | add                 ebx, 0x99264092

        $sequence_7 = { 8b842440f1ffff 059cbb63b8 f7d4 f7d4 2de623626c 8d09 81eb87b68c75 }
            // n = 7, score = 100
            //   8b842440f1ffff       | mov                 eax, dword ptr [esp - 0xec0]
            //   059cbb63b8           | add                 eax, 0xb863bb9c
            //   f7d4                 | not                 esp
            //   f7d4                 | not                 esp
            //   2de623626c           | sub                 eax, 0x6c6223e6
            //   8d09                 | lea                 ecx, [ecx]
            //   81eb87b68c75         | sub                 ebx, 0x758cb687

        $sequence_8 = { 89842400f5ffff 8bc0 8b842400f5ffff 2de49557e5 90 }
            // n = 5, score = 100
            //   89842400f5ffff       | mov                 dword ptr [esp - 0xb00], eax
            //   8bc0                 | mov                 eax, eax
            //   8b842400f5ffff       | mov                 eax, dword ptr [esp - 0xb00]
            //   2de49557e5           | sub                 eax, 0xe55795e4
            //   90                   | nop                 

        $sequence_9 = { 8d8568fbffff 50 ff15???????? 50 }
            // n = 4, score = 100
            //   8d8568fbffff         | lea                 eax, [ebp - 0x498]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   50                   | push                eax

        $sequence_10 = { 8b842410f2ffff 81c39158540b 90 81c387af0f9d 95 89ac2430f3ffff }
            // n = 6, score = 100
            //   8b842410f2ffff       | mov                 eax, dword ptr [esp - 0xdf0]
            //   81c39158540b         | add                 ebx, 0xb545891
            //   90                   | nop                 
            //   81c387af0f9d         | add                 ebx, 0x9d0faf87
            //   95                   | xchg                eax, ebp
            //   89ac2430f3ffff       | mov                 dword ptr [esp - 0xcd0], ebp

        $sequence_11 = { 2d787c6ae6 90 05a2570e84 f7d0 }
            // n = 4, score = 100
            //   2d787c6ae6           | sub                 eax, 0xe66a7c78
            //   90                   | nop                 
            //   05a2570e84           | add                 eax, 0x840e57a2
            //   f7d0                 | not                 eax

        $sequence_12 = { 87f6 81eba762756e 8bdb 0519a01e7f 95 89ac2420f1ffff }
            // n = 6, score = 100
            //   87f6                 | xchg                esi, esi
            //   81eba762756e         | sub                 ebx, 0x6e7562a7
            //   8bdb                 | mov                 ebx, ebx
            //   0519a01e7f           | add                 eax, 0x7f1ea019
            //   95                   | xchg                eax, ebp
            //   89ac2420f1ffff       | mov                 dword ptr [esp - 0xee0], ebp

        $sequence_13 = { 81ebd648f015 81c30e6a05d3 81c38a5df633 2d6f2a1e46 }
            // n = 4, score = 100
            //   81ebd648f015         | sub                 ebx, 0x15f048d6
            //   81c30e6a05d3         | add                 ebx, 0xd3056a0e
            //   81c38a5df633         | add                 ebx, 0x33f65d8a
            //   2d6f2a1e46           | sub                 eax, 0x461e2a6f

        $sequence_14 = { 0596b0efd9 81eb4392fb3e 05c0b6d128 81eb26ad18b7 81eb7eca9393 }
            // n = 5, score = 100
            //   0596b0efd9           | add                 eax, 0xd9efb096
            //   81eb4392fb3e         | sub                 ebx, 0x3efb9243
            //   05c0b6d128           | add                 eax, 0x28d1b6c0
            //   81eb26ad18b7         | sub                 ebx, 0xb718ad26
            //   81eb7eca9393         | sub                 ebx, 0x9393ca7e

        $sequence_15 = { 8be4 81eb1b1f1791 90 81c346ad0895 8bff 81c3f1bd3edf 9b }
            // n = 7, score = 100
            //   8be4                 | mov                 esp, esp
            //   81eb1b1f1791         | sub                 ebx, 0x91171f1b
            //   90                   | nop                 
            //   81c346ad0895         | add                 ebx, 0x9508ad46
            //   8bff                 | mov                 edi, edi
            //   81c3f1bd3edf         | add                 ebx, 0xdf3ebdf1
            //   9b                   | wait                

    condition:
        7 of them
}
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