SYMBOLCOMMON_NAMEaka. SYNONYMS
win.socks5_systemz (Back to overview)

Socks5Systemz

aka: ProxyBox
VTCollection     URLhaus    

The Socks5 Systemz malware is a proxy botnet distributed via the PrivateLoader and Amadey loaders. Active since at least 2016, this botnet infects devices to use them as proxies for malicious activities, offering access for prices ranging from $1 to $140 per day in cryptocurrency. It employs a domain generation algorithm (DGA) to evade detection and enhance its resilience. Persistence is maintained through a Windows service named ContentDWSvc, with the malware injected into memory via a file called previewer.exe. To date, it has compromised approximately 10,000 devices globally, excluding Russia.

References
2026-03-30 ⋅ Synthient ⋅ Synthient
ProxyBox: Socks5Systemz Lives On
Socks5Systemz
2024-12-03 ⋅ BitSight ⋅ Bitsight TRACE
PROXY.AM Powered by Socks5Systemz Botnet
Socks5Systemz
2024-03-09 ⋅ Asobancaria ⋅ CSIRT Financiero
New Backdoor Activity Socks5Systemz
Socks5Systemz
2024-01-30 ⋅ ANY.RUN ⋅ Lena (LambdaMamba)
CrackedCantil: A Malware Symphony Breakdown - PrivateLoader, Smoke, Lumma, RedLine, RisePro, Amadey, Stealc, Socks5Systemz, STOP
Amadey CrackedCantil Lumma Stealer PrivateLoader RedLine Stealer RisePro SmokeLoader Socks5Systemz Stealc STOP
2023-11-02 ⋅ BitSight ⋅ BitSight
Unveiling Socks5Systemz: The Rise of a New Proxy Service via PrivateLoader and Amadey
Amadey PrivateLoader Socks5Systemz
2023-11-02 ⋅ BitSight ⋅ BitSight
Unveiling Socks5Systemz: The Rise of a New Proxy Service via PrivateLoader and Amadey
Amadey PrivateLoader Socks5Systemz
Yara Rules
[TLP:WHITE] win_socks5_systemz_auto (20260917 | Detects win.socks5_systemz.)
rule win_socks5_systemz_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.socks5_systemz."
        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.socks5_systemz"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { 50 8d4c2440 e8???????? c744244824000000 8974244c c74424640f000000 c744246000000000 }
            // n = 7, score = 500
            //   50                   | push                eax
            //   8d4c2440             | lea                 ecx, [esp + 0x40]
            //   e8????????           |                     
            //   c744244824000000     | mov                 dword ptr [esp + 0x48], 0x24
            //   8974244c             | mov                 dword ptr [esp + 0x4c], esi
            //   c74424640f000000     | mov                 dword ptr [esp + 0x64], 0xf
            //   c744246000000000     | mov                 dword ptr [esp + 0x60], 0

        $sequence_1 = { 53 ff15???????? 8b0e e8???????? 83c608 3bf7 7593 }
            // n = 7, score = 500
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   8b0e                 | mov                 ecx, dword ptr [esi]
            //   e8????????           |                     
            //   83c608               | add                 esi, 8
            //   3bf7                 | cmp                 esi, edi
            //   7593                 | jne                 0xffffff95

        $sequence_2 = { 59 59 5d c3 a1???????? c3 6a08 }
            // n = 7, score = 500
            //   59                   | pop                 ecx
            //   59                   | pop                 ecx
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   a1????????           |                     
            //   c3                   | ret                 
            //   6a08                 | push                8

        $sequence_3 = { 53 e8???????? 8b5c241c 8bd0 83c408 8bca 33c0 }
            // n = 7, score = 500
            //   53                   | push                ebx
            //   e8????????           |                     
            //   8b5c241c             | mov                 ebx, dword ptr [esp + 0x1c]
            //   8bd0                 | mov                 edx, eax
            //   83c408               | add                 esp, 8
            //   8bca                 | mov                 ecx, edx
            //   33c0                 | xor                 eax, eax

        $sequence_4 = { 8d4c2414 e8???????? c744241c01000000 89742420 c74424380f000000 c744243400000000 c644242400 }
            // n = 7, score = 500
            //   8d4c2414             | lea                 ecx, [esp + 0x14]
            //   e8????????           |                     
            //   c744241c01000000     | mov                 dword ptr [esp + 0x1c], 1
            //   89742420             | mov                 dword ptr [esp + 0x20], esi
            //   c74424380f000000     | mov                 dword ptr [esp + 0x38], 0xf
            //   c744243400000000     | mov                 dword ptr [esp + 0x34], 0
            //   c644242400           | mov                 byte ptr [esp + 0x24], 0

        $sequence_5 = { 50 ff7314 ff7310 e8???????? 8b4310 83c410 8b3d???????? }
            // n = 7, score = 500
            //   50                   | push                eax
            //   ff7314               | push                dword ptr [ebx + 0x14]
            //   ff7310               | push                dword ptr [ebx + 0x10]
            //   e8????????           |                     
            //   8b4310               | mov                 eax, dword ptr [ebx + 0x10]
            //   83c410               | add                 esp, 0x10
            //   8b3d????????         |                     

        $sequence_6 = { 33c4 50 8d442424 64a300000000 a1???????? 83f8ff 7508 }
            // n = 7, score = 500
            //   33c4                 | xor                 eax, esp
            //   50                   | push                eax
            //   8d442424             | lea                 eax, [esp + 0x24]
            //   64a300000000         | mov                 dword ptr fs:[0], eax
            //   a1????????           |                     
            //   83f8ff               | cmp                 eax, -1
            //   7508                 | jne                 0xa

        $sequence_7 = { 0f8393000000 8b07 89442404 8d442404 50 e8???????? f744240400000080 }
            // n = 7, score = 500
            //   0f8393000000         | jae                 0x99
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   89442404             | mov                 dword ptr [esp + 4], eax
            //   8d442404             | lea                 eax, [esp + 4]
            //   50                   | push                eax
            //   e8????????           |                     
            //   f744240400000080     | test                dword ptr [esp + 4], 0x80000000

    condition:
        7 of them and filesize < 1417216
}
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