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 (20210616 | Detects win.lowball.)
rule win_lowball_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        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 = "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 = { 0f8452010000 a1???????? 8a0d???????? 89842420020000 888c2424020000 }
            // n = 5, score = 100
            //   0f8452010000         | je                  0x158
            //   a1????????           |                     
            //   8a0d????????         |                     
            //   89842420020000       | mov                 dword ptr [esp + 0x220], eax
            //   888c2424020000       | mov                 byte ptr [esp + 0x224], cl

        $sequence_1 = { b93f000000 33c0 8dbc2425020000 8d942420020000 }
            // n = 4, score = 100
            //   b93f000000           | mov                 ecx, 0x3f
            //   33c0                 | xor                 eax, eax
            //   8dbc2425020000       | lea                 edi, dword ptr [esp + 0x225]
            //   8d942420020000       | lea                 edx, dword ptr [esp + 0x220]

        $sequence_2 = { 8974240c 0f84a2010000 8b8c2420060000 53 6a00 6a00 }
            // n = 6, score = 100
            //   8974240c             | mov                 dword ptr [esp + 0xc], esi
            //   0f84a2010000         | je                  0x1a8
            //   8b8c2420060000       | mov                 ecx, dword ptr [esp + 0x620]
            //   53                   | push                ebx
            //   6a00                 | push                0
            //   6a00                 | push                0

        $sequence_3 = { 8bf0 85f6 89742410 0f84bf000000 8b8c241c020000 }
            // n = 5, score = 100
            //   8bf0                 | mov                 esi, eax
            //   85f6                 | test                esi, esi
            //   89742410             | mov                 dword ptr [esp + 0x10], esi
            //   0f84bf000000         | je                  0xc5
            //   8b8c241c020000       | mov                 ecx, dword ptr [esp + 0x21c]

        $sequence_4 = { 8bcb 4f c1e902 f3a5 8bcb 8d9424480b0000 83e103 }
            // n = 7, score = 100
            //   8bcb                 | mov                 ecx, ebx
            //   4f                   | dec                 edi
            //   c1e902               | shr                 ecx, 2
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   8bcb                 | mov                 ecx, ebx
            //   8d9424480b0000       | lea                 edx, dword ptr [esp + 0xb48]
            //   83e103               | and                 ecx, 3

        $sequence_5 = { 85ed 7459 53 8b9c242c020000 }
            // n = 4, score = 100
            //   85ed                 | test                ebp, ebp
            //   7459                 | je                  0x5b
            //   53                   | push                ebx
            //   8b9c242c020000       | mov                 ebx, dword ptr [esp + 0x22c]

        $sequence_6 = { 8974240c 0f84a2010000 8b8c2420060000 53 6a00 6a00 6a03 }
            // n = 7, score = 100
            //   8974240c             | mov                 dword ptr [esp + 0xc], esi
            //   0f84a2010000         | je                  0x1a8
            //   8b8c2420060000       | mov                 ecx, dword ptr [esp + 0x620]
            //   53                   | push                ebx
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a03                 | push                3

        $sequence_7 = { 33c0 5b 81c4400e0000 c21000 83c9ff 33c0 }
            // n = 6, score = 100
            //   33c0                 | xor                 eax, eax
            //   5b                   | pop                 ebx
            //   81c4400e0000         | add                 esp, 0xe40
            //   c21000               | ret                 0x10
            //   83c9ff               | or                  ecx, 0xffffffff
            //   33c0                 | xor                 eax, eax

        $sequence_8 = { 33c0 eb05 1bc0 83d8ff 85c0 8dbc2424030000 }
            // n = 6, score = 100
            //   33c0                 | xor                 eax, eax
            //   eb05                 | jmp                 7
            //   1bc0                 | sbb                 eax, eax
            //   83d8ff               | sbb                 eax, -1
            //   85c0                 | test                eax, eax
            //   8dbc2424030000       | lea                 edi, dword ptr [esp + 0x324]

        $sequence_9 = { 85c0 5b 7408 c744240c01000000 8b742414 55 ff15???????? }
            // n = 7, score = 100
            //   85c0                 | test                eax, eax
            //   5b                   | pop                 ebx
            //   7408                 | je                  0xa
            //   c744240c01000000     | mov                 dword ptr [esp + 0xc], 1
            //   8b742414             | mov                 esi, dword ptr [esp + 0x14]
            //   55                   | push                ebp
            //   ff15????????         |                     

    condition:
        7 of them and filesize < 40960
}
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