SYMBOLCOMMON_NAMEaka. SYNONYMS
win.crutch (Back to overview)

Crutch

Actor(s): Turla


There is no description at this point.

References
2021-04-29ESET ResearchRobert Lipovsky, Matthieu Faou, Tony Anscombe, Andy Garth, Daniel Chromek
@techreport{lipovsky:20210429:eset:ff67b6c, author = {Robert Lipovsky and Matthieu Faou and Tony Anscombe and Andy Garth and Daniel Chromek}, title = {{ESET Industry Report on Government: Targeted but not alone}}, date = {2021-04-29}, institution = {ESET Research}, url = {https://www.welivesecurity.com/wp-content/uploads/2021/04/ESET_Industry_Report_Government.pdf}, language = {English}, urldate = {2021-05-03} } ESET Industry Report on Government: Targeted but not alone
Exaramel Crutch Exaramel HyperBro HyperSSL InvisiMole XDSpy
2020-12-02ESET ResearchMatthieu Faou
@online{faou:20201202:turla:7f8c935, author = {Matthieu Faou}, title = {{Turla Crutch: Keeping the “back door” open}}, date = {2020-12-02}, organization = {ESET Research}, url = {https://www.welivesecurity.com/2020/12/02/turla-crutch-keeping-back-door-open/}, language = {English}, urldate = {2020-12-08} } Turla Crutch: Keeping the “back door” open
Crutch Gazer Turla
Yara Rules
[TLP:WHITE] win_crutch_auto (20230125 | Detects win.crutch.)
rule win_crutch_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.crutch."
        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.crutch"
        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 = { 3bd8 7233 8b9638020000 51 52 68???????? 56 }
            // n = 7, score = 100
            //   3bd8                 | cmp                 ebx, eax
            //   7233                 | jb                  0x35
            //   8b9638020000         | mov                 edx, dword ptr [esi + 0x238]
            //   51                   | push                ecx
            //   52                   | push                edx
            //   68????????           |                     
            //   56                   | push                esi

        $sequence_1 = { e9???????? 8b4708 83f807 0f873a010000 ff248550810310 80fb20 0f842a010000 }
            // n = 7, score = 100
            //   e9????????           |                     
            //   8b4708               | mov                 eax, dword ptr [edi + 8]
            //   83f807               | cmp                 eax, 7
            //   0f873a010000         | ja                  0x140
            //   ff248550810310       | jmp                 dword ptr [eax*4 + 0x10038150]
            //   80fb20               | cmp                 bl, 0x20
            //   0f842a010000         | je                  0x130

        $sequence_2 = { 50 e8???????? 83c40c 8d4601 8bce 50 e8???????? }
            // n = 7, score = 100
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   8d4601               | lea                 eax, [esi + 1]
            //   8bce                 | mov                 ecx, esi
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_3 = { 51 e8???????? 83c404 85c0 741d 4f 83ed01 }
            // n = 7, score = 100
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   85c0                 | test                eax, eax
            //   741d                 | je                  0x1f
            //   4f                   | dec                 edi
            //   83ed01               | sub                 ebp, 1

        $sequence_4 = { 8b4524 83f802 7e07 83f811 7d02 8929 833b00 }
            // n = 7, score = 100
            //   8b4524               | mov                 eax, dword ptr [ebp + 0x24]
            //   83f802               | cmp                 eax, 2
            //   7e07                 | jle                 9
            //   83f811               | cmp                 eax, 0x11
            //   7d02                 | jge                 4
            //   8929                 | mov                 dword ptr [ecx], ebp
            //   833b00               | cmp                 dword ptr [ebx], 0

        $sequence_5 = { 8b542418 8b44241c 898e78070000 8b4c2420 89967c070000 898680070000 898e84070000 }
            // n = 7, score = 100
            //   8b542418             | mov                 edx, dword ptr [esp + 0x18]
            //   8b44241c             | mov                 eax, dword ptr [esp + 0x1c]
            //   898e78070000         | mov                 dword ptr [esi + 0x778], ecx
            //   8b4c2420             | mov                 ecx, dword ptr [esp + 0x20]
            //   89967c070000         | mov                 dword ptr [esi + 0x77c], edx
            //   898680070000         | mov                 dword ptr [esi + 0x780], eax
            //   898e84070000         | mov                 dword ptr [esi + 0x784], ecx

        $sequence_6 = { 7212 6a09 53 57 55 e8???????? 83c410 }
            // n = 7, score = 100
            //   7212                 | jb                  0x14
            //   6a09                 | push                9
            //   53                   | push                ebx
            //   57                   | push                edi
            //   55                   | push                ebp
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10

        $sequence_7 = { 741a 85c9 0f8cb9010000 7f08 85c0 0f86af010000 }
            // n = 6, score = 100
            //   741a                 | je                  0x1c
            //   85c9                 | test                ecx, ecx
            //   0f8cb9010000         | jl                  0x1bf
            //   7f08                 | jg                  0xa
            //   85c0                 | test                eax, eax
            //   0f86af010000         | jbe                 0x1b5

        $sequence_8 = { 899ed4000000 899ef8000000 899ed8000000 8b9798000000 52 ff15???????? 8b87ac000000 }
            // n = 7, score = 100
            //   899ed4000000         | mov                 dword ptr [esi + 0xd4], ebx
            //   899ef8000000         | mov                 dword ptr [esi + 0xf8], ebx
            //   899ed8000000         | mov                 dword ptr [esi + 0xd8], ebx
            //   8b9798000000         | mov                 edx, dword ptr [edi + 0x98]
            //   52                   | push                edx
            //   ff15????????         |                     
            //   8b87ac000000         | mov                 eax, dword ptr [edi + 0xac]

        $sequence_9 = { 8945f0 8845c8 660f1345d0 660f1345d8 8945e0 8945e4 8945e8 }
            // n = 7, score = 100
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   8845c8               | mov                 byte ptr [ebp - 0x38], al
            //   660f1345d0           | movlpd              qword ptr [ebp - 0x30], xmm0
            //   660f1345d8           | movlpd              qword ptr [ebp - 0x28], xmm0
            //   8945e0               | mov                 dword ptr [ebp - 0x20], eax
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax

    condition:
        7 of them and filesize < 1067008
}
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