SYMBOLCOMMON_NAMEaka. SYNONYMS
win.gearshift (Back to overview)

GEARSHIFT

Actor(s): APT41


According to FireEye, GEARSHIFT is a memory-only dropper for two keylogger DLLs. It is designed to replace a legitimate Fax Service DLL.

References
2019-08-09FireEyeFireEye
@online{fireeye:20190809:double:40f736e, author = {FireEye}, title = {{Double Dragon APT41, a dual espionage and cyber crime operation}}, date = {2019-08-09}, organization = {FireEye}, url = {https://content.fireeye.com/apt-41/rpt-apt41/}, language = {English}, urldate = {2019-12-18} } Double Dragon APT41, a dual espionage and cyber crime operation
CLASSFON crackshot CROSSWALK GEARSHIFT HIGHNOON HIGHNOON.BIN JUMPALL poisonplug Winnti
Yara Rules
[TLP:WHITE] win_gearshift_auto (20220411 | Detects win.gearshift.)
rule win_gearshift_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-04-08"
        version = "1"
        description = "Detects win.gearshift."
        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.gearshift"
        malpedia_rule_date = "20220405"
        malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a"
        malpedia_version = "20220411"
        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 = { 488d1587ae0000 498bcc 48894528 ff15???????? 488d1563af0000 498bcc }
            // n = 6, score = 200
            //   488d1587ae0000       | inc                 ecx
            //   498bcc               | push                esi
            //   48894528             | inc                 ecx
            //   ff15????????         |                     
            //   488d1563af0000       | push                edi
            //   498bcc               | dec                 eax

        $sequence_1 = { 48895c2420 ff15???????? 488d1597a90000 488bc8 }
            // n = 4, score = 200
            //   48895c2420           | dec                 esp
            //   ff15????????         |                     
            //   488d1597a90000       | lea                 ecx, dword ptr [0xffff7ad2]
            //   488bc8               | dec                 ecx

        $sequence_2 = { c705????????00010000 b800010000 488b8c24c0000000 4833cc e8???????? }
            // n = 5, score = 200
            //   c705????????00010000     |     
            //   b800010000           | dec                 eax
            //   488b8c24c0000000     | mov                 ebx, dword ptr [esp + 0x30]
            //   4833cc               | dec                 eax
            //   e8????????           |                     

        $sequence_3 = { 7505 e8???????? 488d3d803e0300 41b804010000 33c9 488bd7 }
            // n = 6, score = 200
            //   7505                 | dec                 eax
            //   e8????????           |                     
            //   488d3d803e0300       | lea                 edx, dword ptr [0xb814]
            //   41b804010000         | dec                 eax
            //   33c9                 | test                eax, eax
            //   488bd7               | je                  0x7b9

        $sequence_4 = { 755a 488d0db30c0000 e8???????? 488d1d87680000 }
            // n = 4, score = 200
            //   755a                 | jne                 0xffffff33
            //   488d0db30c0000       | dec                 esp
            //   e8????????           |                     
            //   488d1d87680000       | lea                 ecx, dword ptr [0xffffa974]

        $sequence_5 = { 7ce0 488b7c2438 488b4b10 e8???????? 488b4b08 488b742430 4885c9 }
            // n = 7, score = 200
            //   7ce0                 | dec                 eax
            //   488b7c2438           | add                 ebp, 2
            //   488b4b10             | cmp                 edi, dword ptr [ebx + 0x18]
            //   e8????????           |                     
            //   488b4b08             | jb                  0xbf0
            //   488b742430           | xor                 eax, eax
            //   4885c9               | dec                 eax

        $sequence_6 = { 66666666660f1f840000000000 48b80000000000000080 4885c8 7405 0fb7d1 eb09 }
            // n = 6, score = 200
            //   66666666660f1f840000000000     | mov    dword ptr [esp + 0x40], eax
            //   48b80000000000000080     | dec    eax
            //   4885c8               | mov                 eax, dword ptr [esp + 0x40]
            //   7405                 | movzx               eax, byte ptr [eax]
            //   0fb7d1               | mov                 byte ptr [esp + 0x20], al
            //   eb09                 | jmp                 0xbf5

        $sequence_7 = { 44896c2444 ff15???????? 85c0 741a }
            // n = 4, score = 200
            //   44896c2444           | dec                 ebp
            //   ff15????????         |                     
            //   85c0                 | add                 eax, dword ptr [ecx + ecx*8 + 0x16ae0]
            //   741a                 | inc                 ecx

        $sequence_8 = { 4533c0 33d2 498bcc 44896c2428 48897c2420 ff15???????? ba01000000 }
            // n = 7, score = 200
            //   4533c0               | jne                 0x1a3
            //   33d2                 | dec                 eax
            //   498bcc               | lea                 eax, dword ptr [0xfc87]
            //   44896c2428           | jmp                 0x1a7
            //   48897c2420           | dec                 eax
            //   ff15????????         |                     
            //   ba01000000           | add                 eax, 0x10

        $sequence_9 = { ffd0 488b4d7f 85c0 490f48cc }
            // n = 4, score = 200
            //   ffd0                 | cmp                 eax, 5
            //   488b4d7f             | jne                 0x60f
            //   85c0                 | mov                 eax, dword ptr [esp + 0x28]
            //   490f48cc             | mov                 eax, dword ptr [esp + 0x28]

    condition:
        7 of them and filesize < 540672
}
[TLP:WHITE] win_gearshift_w0   (20191207 | No description)
rule win_gearshift_w0 {
    meta:
        author = "Bundesamt fuer Verfassungsschutz"
        source = "https://www.verfassungsschutz.de/download/anlage-2019-12-bfv-cyber-brief-2019-01.txt"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.gearshift"
        malpedia_version = "20191207"
        malpedia_sharing = "TLP:WHITE"
        malpedia_license = ""
    strings:
        $b1 = { 4C 8D 41 24 33 D2 B9 03 00 1F 00 FF 9? F8 00 00 00 48 85 C0 74 }
        $b2 = { 4C 8B 4? 08 BA 01 00 00 00 49 8B C? FF D0 85 C0 [2-6] C7 4? 1C 01 00 00 00 B8 01 00 00 00 }
        $b3 = { 8B 4B E4 8B 53 EC 41 B8 00 40 00 00 4? 0B C? FF 9? B8 00 00 00 EB }
    condition:
        (2 of ($b*))
}
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