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 (20230715 | Detects win.crutch.)
rule win_crutch_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        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 = "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 = { 7477 8b5c2420 8b0b 83b9a403000000 7446 8b4560 85c0 }
            // n = 7, score = 100
            //   7477                 | je                  0x79
            //   8b5c2420             | mov                 ebx, dword ptr [esp + 0x20]
            //   8b0b                 | mov                 ecx, dword ptr [ebx]
            //   83b9a403000000       | cmp                 dword ptr [ecx + 0x3a4], 0
            //   7446                 | je                  0x48
            //   8b4560               | mov                 eax, dword ptr [ebp + 0x60]
            //   85c0                 | test                eax, eax

        $sequence_1 = { c6442e0100 e8???????? 8b54244c 8b442448 8b4c243c 52 50 }
            // n = 7, score = 100
            //   c6442e0100           | mov                 byte ptr [esi + ebp + 1], 0
            //   e8????????           |                     
            //   8b54244c             | mov                 edx, dword ptr [esp + 0x4c]
            //   8b442448             | mov                 eax, dword ptr [esp + 0x48]
            //   8b4c243c             | mov                 ecx, dword ptr [esp + 0x3c]
            //   52                   | push                edx
            //   50                   | push                eax

        $sequence_2 = { 5e 8bc3 5b e9???????? 8b742418 85f6 7477 }
            // n = 7, score = 100
            //   5e                   | pop                 esi
            //   8bc3                 | mov                 eax, ebx
            //   5b                   | pop                 ebx
            //   e9????????           |                     
            //   8b742418             | mov                 esi, dword ptr [esp + 0x18]
            //   85f6                 | test                esi, esi
            //   7477                 | je                  0x79

        $sequence_3 = { 51 50 e8???????? 8b542424 83c40c 3bd3 0f8435feffff }
            // n = 7, score = 100
            //   51                   | push                ecx
            //   50                   | push                eax
            //   e8????????           |                     
            //   8b542424             | mov                 edx, dword ptr [esp + 0x24]
            //   83c40c               | add                 esp, 0xc
            //   3bd3                 | cmp                 edx, ebx
            //   0f8435feffff         | je                  0xfffffe3b

        $sequence_4 = { e8???????? 83c404 8be8 eb1b 55 ff15???????? 8b442410 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   8be8                 | mov                 ebp, eax
            //   eb1b                 | jmp                 0x1d
            //   55                   | push                ebp
            //   ff15????????         |                     
            //   8b442410             | mov                 eax, dword ptr [esp + 0x10]

        $sequence_5 = { 8bec 56 8b7508 833cf5906e071000 7513 56 e8???????? }
            // n = 7, score = 100
            //   8bec                 | mov                 ebp, esp
            //   56                   | push                esi
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]
            //   833cf5906e071000     | cmp                 dword ptr [esi*8 + 0x10076e90], 0
            //   7513                 | jne                 0x15
            //   56                   | push                esi
            //   e8????????           |                     

        $sequence_6 = { ffd0 83c404 83ceff 895c245c 899dc04a0000 895d08 83feff }
            // n = 7, score = 100
            //   ffd0                 | call                eax
            //   83c404               | add                 esp, 4
            //   83ceff               | or                  esi, 0xffffffff
            //   895c245c             | mov                 dword ptr [esp + 0x5c], ebx
            //   899dc04a0000         | mov                 dword ptr [ebp + 0x4ac0], ebx
            //   895d08               | mov                 dword ptr [ebp + 8], ebx
            //   83feff               | cmp                 esi, -1

        $sequence_7 = { 33ff 3bc7 7422 50 ff15???????? 83c404 89bed0010000 }
            // n = 7, score = 100
            //   33ff                 | xor                 edi, edi
            //   3bc7                 | cmp                 eax, edi
            //   7422                 | je                  0x24
            //   50                   | push                eax
            //   ff15????????         |                     
            //   83c404               | add                 esp, 4
            //   89bed0010000         | mov                 dword ptr [esi + 0x1d0], edi

        $sequence_8 = { 8d442434 50 8d4c2468 51 57 e8???????? 83c428 }
            // n = 7, score = 100
            //   8d442434             | lea                 eax, [esp + 0x34]
            //   50                   | push                eax
            //   8d4c2468             | lea                 ecx, [esp + 0x68]
            //   51                   | push                ecx
            //   57                   | push                edi
            //   e8????????           |                     
            //   83c428               | add                 esp, 0x28

        $sequence_9 = { 837d4010 c745280f000000 c7452400000000 c6451400 720b ff752c e8???????? }
            // n = 7, score = 100
            //   837d4010             | cmp                 dword ptr [ebp + 0x40], 0x10
            //   c745280f000000       | mov                 dword ptr [ebp + 0x28], 0xf
            //   c7452400000000       | mov                 dword ptr [ebp + 0x24], 0
            //   c6451400             | mov                 byte ptr [ebp + 0x14], 0
            //   720b                 | jb                  0xd
            //   ff752c               | push                dword ptr [ebp + 0x2c]
            //   e8????????           |                     

    condition:
        7 of them and filesize < 1067008
}
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