SYMBOLCOMMON_NAMEaka. SYNONYMS
win.crutch (Back to overview)

Crutch

Actor(s): Turla Group


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 Group
Yara Rules
[TLP:WHITE] win_crutch_auto (20210616 | Detects win.crutch.)
rule win_crutch_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        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 = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 7425 8b4b14 8d442414 50 8b4318 99 }
            // n = 6, score = 100
            //   7425                 | je                  0x27
            //   8b4b14               | mov                 ecx, dword ptr [ebx + 0x14]
            //   8d442414             | lea                 eax, dword ptr [esp + 0x14]
            //   50                   | push                eax
            //   8b4318               | mov                 eax, dword ptr [ebx + 0x18]
            //   99                   | cdq                 

        $sequence_1 = { 83c440 c3 8b4e0c 8b5108 57 89542424 c744242807000000 }
            // n = 7, score = 100
            //   83c440               | add                 esp, 0x40
            //   c3                   | ret                 
            //   8b4e0c               | mov                 ecx, dword ptr [esi + 0xc]
            //   8b5108               | mov                 edx, dword ptr [ecx + 8]
            //   57                   | push                edi
            //   89542424             | mov                 dword ptr [esp + 0x24], edx
            //   c744242807000000     | mov                 dword ptr [esp + 0x28], 7

        $sequence_2 = { 8b0e 68???????? 51 e8???????? 83c40c bf43000000 ebae }
            // n = 7, score = 100
            //   8b0e                 | mov                 ecx, dword ptr [esi]
            //   68????????           |                     
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   bf43000000           | mov                 edi, 0x43
            //   ebae                 | jmp                 0xffffffb0

        $sequence_3 = { 57 8b7c2414 8b1f 8bb788050000 8d442414 50 8bc7 }
            // n = 7, score = 100
            //   57                   | push                edi
            //   8b7c2414             | mov                 edi, dword ptr [esp + 0x14]
            //   8b1f                 | mov                 ebx, dword ptr [edi]
            //   8bb788050000         | mov                 esi, dword ptr [edi + 0x588]
            //   8d442414             | lea                 eax, dword ptr [esp + 0x14]
            //   50                   | push                eax
            //   8bc7                 | mov                 eax, edi

        $sequence_4 = { 6a00 51 e8???????? 83c40c 837c243400 8944245c 745e }
            // n = 7, score = 100
            //   6a00                 | push                0
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   837c243400           | cmp                 dword ptr [esp + 0x34], 0
            //   8944245c             | mov                 dword ptr [esp + 0x5c], eax
            //   745e                 | je                  0x60

        $sequence_5 = { 8bcb e8???????? 8b45d4 8b13 8b08 890b 8910 }
            // n = 7, score = 100
            //   8bcb                 | mov                 ecx, ebx
            //   e8????????           |                     
            //   8b45d4               | mov                 eax, dword ptr [ebp - 0x2c]
            //   8b13                 | mov                 edx, dword ptr [ebx]
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   890b                 | mov                 dword ptr [ebx], ecx
            //   8910                 | mov                 dword ptr [eax], edx

        $sequence_6 = { 837db408 8d45a0 0f4345a0 50 ff15???????? 83f8ff 8d4da0 }
            // n = 7, score = 100
            //   837db408             | cmp                 dword ptr [ebp - 0x4c], 8
            //   8d45a0               | lea                 eax, dword ptr [ebp - 0x60]
            //   0f4345a0             | cmovae              eax, dword ptr [ebp - 0x60]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   83f8ff               | cmp                 eax, -1
            //   8d4da0               | lea                 ecx, dword ptr [ebp - 0x60]

        $sequence_7 = { 742d 8b44241c 8b08 6a01 53 8d6e50 55 }
            // n = 7, score = 100
            //   742d                 | je                  0x2f
            //   8b44241c             | mov                 eax, dword ptr [esp + 0x1c]
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   6a01                 | push                1
            //   53                   | push                ebx
            //   8d6e50               | lea                 ebp, dword ptr [esi + 0x50]
            //   55                   | push                ebp

        $sequence_8 = { 898f04060000 898700060000 8b8f10060000 f6c110 0f8582040000 8b87dc010000 85c0 }
            // n = 7, score = 100
            //   898f04060000         | mov                 dword ptr [edi + 0x604], ecx
            //   898700060000         | mov                 dword ptr [edi + 0x600], eax
            //   8b8f10060000         | mov                 ecx, dword ptr [edi + 0x610]
            //   f6c110               | test                cl, 0x10
            //   0f8582040000         | jne                 0x488
            //   8b87dc010000         | mov                 eax, dword ptr [edi + 0x1dc]
            //   85c0                 | test                eax, eax

        $sequence_9 = { c645fc1e 8325????????00 891d???????? c605????????00 be???????? 56 e8???????? }
            // n = 7, score = 100
            //   c645fc1e             | mov                 byte ptr [ebp - 4], 0x1e
            //   8325????????00       |                     
            //   891d????????         |                     
            //   c605????????00       |                     
            //   be????????           |                     
            //   56                   | push                esi
            //   e8????????           |                     

    condition:
        7 of them and filesize < 1067008
}
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