SYMBOLCOMMON_NAMEaka. SYNONYMS
win.clambling (Back to overview)

Clambling


Clambling was discovered by Trend Micro and TalentJump. It is a custom malware used by an actor they refer to as DRBControl, which targets gambling and betting companies in Southeast Asia. One version of Clambling uses Dropbox as C&C channel to hide its communication.

References
2021-01-04ProferoProfero, SecurityJoes
@techreport{profero:20210104:apt27:a281786, author = {Profero and SecurityJoes}, title = {{APT27 Turns to Ransomware}}, date = {2021-01-04}, institution = {Profero}, url = {https://shared-public-reports.s3-eu-west-1.amazonaws.com/APT27+turns+to+ransomware.pdf}, language = {English}, urldate = {2021-01-10} } APT27 Turns to Ransomware
Clambling
2021-01-04Bleeping ComputerIonut Ilascu
@online{ilascu:20210104:chinas:9677dc6, author = {Ionut Ilascu}, title = {{China's APT hackers move to ransomware attacks}}, date = {2021-01-04}, organization = {Bleeping Computer}, url = {https://www.bleepingcomputer.com/news/security/chinas-apt-hackers-move-to-ransomware-attacks/}, language = {English}, urldate = {2021-01-11} } China's APT hackers move to ransomware attacks
Clambling PlugX
2020-02-18Trend MicroDaniel Lunghi, Cedric Pernet, Kenney Lu, Jamz Yaneza
@techreport{lunghi:20200218:uncovering:d96f725, author = {Daniel Lunghi and Cedric Pernet and Kenney Lu and Jamz Yaneza}, title = {{Uncovering DRBControl}}, date = {2020-02-18}, institution = {Trend Micro}, url = {https://documents.trendmicro.com/assets/white_papers/wp-uncovering-DRBcontrol.pdf}, language = {English}, urldate = {2020-04-01} } Uncovering DRBControl
Clambling
Yara Rules
[TLP:WHITE] win_clambling_auto (20201023 | autogenerated rule brought to you by yara-signator)
rule win_clambling_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-12-22"
        version = "1"
        description = "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.clambling"
        malpedia_rule_date = "20201222"
        malpedia_hash = "30354d830a29f0fbd3714d93d94dea941d77a130"
        malpedia_version = "20201023"
        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 = { 53 56 57 4881ec70010000 33f6 488bf9 c7401000010000 }
            // n = 7, score = 300
            //   53                   | jmp                 0xae8
            //   56                   | mov                 ecx, 0x40
            //   57                   | xor                 edi, edi
            //   4881ec70010000       | dec                 eax
            //   33f6                 | mov                 ebx, eax
            //   488bf9               | dec                 esp
            //   c7401000010000       | lea                 ebx, [0x18b34]

        $sequence_1 = { 483bc6 7504 8bc6 eb07 488d4c2440 }
            // n = 5, score = 300
            //   483bc6               | je                  0x15f8
            //   7504                 | jmp                 0x1658
            //   8bc6                 | mov                 ebx, eax
            //   eb07                 | test                eax, eax
            //   488d4c2440           | je                  0x1621

        $sequence_2 = { 8bd8 ff15???????? 488bcf ff15???????? 8bc3 }
            // n = 5, score = 300
            //   8bd8                 | dec                 eax
            //   ff15????????         |                     
            //   488bcf               | mov                 eax, dword ptr [ebx + 0x20]
            //   ff15????????         |                     
            //   8bc3                 | dec                 eax

        $sequence_3 = { 488bcf e8???????? 4c8d9c2480100000 8bc3 498b5b18 }
            // n = 5, score = 300
            //   488bcf               | mov                 ebp, eax
            //   e8????????           |                     
            //   4c8d9c2480100000     | dec                 ecx
            //   8bc3                 | cmp                 eax, esp
            //   498b5b18             | jne                 0x1a34

        $sequence_4 = { 8b442450 83f801 7419 83f802 7414 83f803 7508 }
            // n = 7, score = 300
            //   8b442450             | test                esp, esp
            //   83f801               | je                  0x52
            //   7419                 | jl                  0xffffffe9
            //   83f802               | dec                 esp
            //   7414                 | mov                 dword ptr [esp + 0x38], edi
            //   83f803               | mov                 dword ptr [esp + 0x30], 0x84400100
            //   7508                 | dec                 esp

        $sequence_5 = { 85c0 7448 4c8d442434 488bd7 33c9 }
            // n = 5, score = 300
            //   85c0                 | mov                 dword ptr [esp + 0x20], eax
            //   7448                 | inc                 ebp
            //   4c8d442434           | xor                 eax, eax
            //   488bd7               | mov                 edx, 0x40000003
            //   33c9                 | mov                 dword ptr [esp + 0x20], eax

        $sequence_6 = { 4c8d442460 8d5608 488bc8 ff15???????? 3bc6 0f84b5000000 }
            // n = 6, score = 300
            //   4c8d442460           | mov                 dword ptr [esp + 0x68], edi
            //   8d5608               | lea                 eax, [ebp + 5]
            //   488bc8               | mov                 word ptr [esp + 0x60], bp
            //   ff15????????         |                     
            //   3bc6                 | mov                 ebp, 4
            //   0f84b5000000         | dec                 eax

        $sequence_7 = { 48895c2408 4889742410 57 4883ec30 488b05???????? 498bd9 498bf8 }
            // n = 7, score = 300
            //   48895c2408           | inc                 ecx
            //   4889742410           | pop                 esi
            //   57                   | inc                 ecx
            //   4883ec30             | pop                 ebp
            //   488b05????????       |                     
            //   498bd9               | inc                 ecx
            //   498bf8               | pop                 esp

        $sequence_8 = { e8???????? 4c8d9c2450100000 8bc7 498b5b18 }
            // n = 4, score = 300
            //   e8????????           |                     
            //   4c8d9c2450100000     | cmp                 dword ptr [ebx + 0x142a8], eax
            //   8bc7                 | jge                 0x164
            //   498b5b18             | dec                 esp

        $sequence_9 = { ff15???????? 4c8d442458 8d5308 488bc8 }
            // n = 4, score = 300
            //   ff15????????         |                     
            //   4c8d442458           | xor                 ecx, ecx
            //   8d5308               | dec                 eax
            //   488bc8               | mov                 ecx, ebx

    condition:
        7 of them and filesize < 412672
}
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