SYMBOLCOMMON_NAMEaka. SYNONYMS
win.lowball (Back to overview)

LOWBALL

Actor(s): Temper Panda


LOWBALL, uses the legitimate Dropbox cloud-storage
service to act as the CnC server. It uses the Dropbox API with a hardcoded bearer access token and has the ability to download, upload, and execute files. The communication occurs via HTTPS over port 443.

References
2019-08-12Kindred SecurityKindred Security
@online{security:20190812:overview:0726c0a, author = {Kindred Security}, title = {{An Overview of Public Platform C2’s}}, date = {2019-08-12}, organization = {Kindred Security}, url = {https://kindredsec.wordpress.com/2019/08/12/an-overview-of-public-platform-c2s/}, language = {English}, urldate = {2021-07-20} } An Overview of Public Platform C2’s
HTML5 Encoding LOWBALL Makadocs MiniDuke RogueRobinNET RokRAT
2015-12-01FireEyeFireEye Threat Intelligence
@online{intelligence:20151201:chinabased:8836a81, author = {FireEye Threat Intelligence}, title = {{China-based Cyber Threat Group Uses Dropbox for Malware Communications and Targets Hong Kong Media Outlets}}, date = {2015-12-01}, organization = {FireEye}, url = {https://www.fireeye.com/blog/threat-research/2015/11/china-based-threat.html}, language = {English}, urldate = {2019-12-20} } China-based Cyber Threat Group Uses Dropbox for Malware Communications and Targets Hong Kong Media Outlets
BUBBLEWRAP LOWBALL Temper Panda
Yara Rules
[TLP:WHITE] win_lowball_auto (20220516 | Detects win.lowball.)
rule win_lowball_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-05-16"
        version = "1"
        description = "Detects win.lowball."
        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.lowball"
        malpedia_rule_date = "20220513"
        malpedia_hash = "7f4b2229e6ae614d86d74917f6d5b41890e62a26"
        malpedia_version = "20220516"
        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 = { 8dbc241c010000 33c0 f3a5 66a5 a4 }
            // n = 5, score = 100
            //   8dbc241c010000       | lea                 edi, [esp + 0x11c]
            //   33c0                 | xor                 eax, eax
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   66a5                 | movsw               word ptr es:[edi], word ptr [esi]
            //   a4                   | movsb               byte ptr es:[edi], byte ptr [esi]

        $sequence_1 = { f3a4 8d8c24480b0000 51 68???????? 68???????? }
            // n = 5, score = 100
            //   f3a4                 | rep movsb           byte ptr es:[edi], byte ptr [esi]
            //   8d8c24480b0000       | lea                 ecx, [esp + 0xb48]
            //   51                   | push                ecx
            //   68????????           |                     
            //   68????????           |                     

        $sequence_2 = { 8d0480 8d0480 8d04c0 c1e007 50 ff15???????? 8b442410 }
            // n = 7, score = 100
            //   8d0480               | lea                 eax, [eax + eax*4]
            //   8d0480               | lea                 eax, [eax + eax*4]
            //   8d04c0               | lea                 eax, [eax + eax*8]
            //   c1e007               | shl                 eax, 7
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b442410             | mov                 eax, dword ptr [esp + 0x10]

        $sequence_3 = { c74424100a000000 8bc1 8bf7 8bfa 8d942434070000 c1e902 }
            // n = 6, score = 100
            //   c74424100a000000     | mov                 dword ptr [esp + 0x10], 0xa
            //   8bc1                 | mov                 eax, ecx
            //   8bf7                 | mov                 esi, edi
            //   8bfa                 | mov                 edi, edx
            //   8d942434070000       | lea                 edx, [esp + 0x734]
            //   c1e902               | shr                 ecx, 2

        $sequence_4 = { 68???????? 53 ff15???????? 3bc5 89442414 }
            // n = 5, score = 100
            //   68????????           |                     
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   3bc5                 | cmp                 eax, ebp
            //   89442414             | mov                 dword ptr [esp + 0x14], eax

        $sequence_5 = { 49 8bf1 8b942430020000 33c9 85d2 }
            // n = 5, score = 100
            //   49                   | dec                 ecx
            //   8bf1                 | mov                 esi, ecx
            //   8b942430020000       | mov                 edx, dword ptr [esp + 0x230]
            //   33c9                 | xor                 ecx, ecx
            //   85d2                 | test                edx, edx

        $sequence_6 = { 68???????? 52 68???????? 53 ff15???????? 8be8 85ed }
            // n = 7, score = 100
            //   68????????           |                     
            //   52                   | push                edx
            //   68????????           |                     
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   8be8                 | mov                 ebp, eax
            //   85ed                 | test                ebp, ebp

        $sequence_7 = { ffd6 83c40c 85c0 0f84a6000000 6a08 8d842428020000 }
            // n = 6, score = 100
            //   ffd6                 | call                esi
            //   83c40c               | add                 esp, 0xc
            //   85c0                 | test                eax, eax
            //   0f84a6000000         | je                  0xac
            //   6a08                 | push                8
            //   8d842428020000       | lea                 eax, [esp + 0x228]

        $sequence_8 = { 7420 8b542410 56 52 8d84242c020000 6a01 50 }
            // n = 7, score = 100
            //   7420                 | je                  0x22
            //   8b542410             | mov                 edx, dword ptr [esp + 0x10]
            //   56                   | push                esi
            //   52                   | push                edx
            //   8d84242c020000       | lea                 eax, [esp + 0x22c]
            //   6a01                 | push                1
            //   50                   | push                eax

        $sequence_9 = { 8b7c2414 f7d1 49 51 52 56 53 }
            // n = 7, score = 100
            //   8b7c2414             | mov                 edi, dword ptr [esp + 0x14]
            //   f7d1                 | not                 ecx
            //   49                   | dec                 ecx
            //   51                   | push                ecx
            //   52                   | push                edx
            //   56                   | push                esi
            //   53                   | push                ebx

    condition:
        7 of them and filesize < 40960
}
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