rule win_fuxsocy_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.fuxsocy."
        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.fuxsocy"
        malpedia_rule_date = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { 3906 5e 0f94c0 c3 6a10 68???????? e8???????? }
            // n = 7, score = 200
            //   3906                 | cmp                 dword ptr [esi], eax
            //   5e                   | pop                 esi
            //   0f94c0               | sete                al
            //   c3                   | ret                 
            //   6a10                 | push                0x10
            //   68????????           |                     
            //   e8????????           |                     

        $sequence_1 = { 57 f7d8 57 50 ff15???????? 89442444 85c0 }
            // n = 7, score = 200
            //   57                   | push                edi
            //   f7d8                 | neg                 eax
            //   57                   | push                edi
            //   50                   | push                eax
            //   ff15????????         |                     
            //   89442444             | mov                 dword ptr [esp + 0x44], eax
            //   85c0                 | test                eax, eax

        $sequence_2 = { 57 ff15???????? cc 81ecac000000 53 55 56 }
            // n = 7, score = 200
            //   57                   | push                edi
            //   ff15????????         |                     
            //   cc                   | int3                
            //   81ecac000000         | sub                 esp, 0xac
            //   53                   | push                ebx
            //   55                   | push                ebp
            //   56                   | push                esi

        $sequence_3 = { 8bf1 57 8bca e8???????? 8bf8 8bd6 }
            // n = 6, score = 200
            //   8bf1                 | mov                 esi, ecx
            //   57                   | push                edi
            //   8bca                 | mov                 ecx, edx
            //   e8????????           |                     
            //   8bf8                 | mov                 edi, eax
            //   8bd6                 | mov                 edx, esi

        $sequence_4 = { c745c43c000000 c745c840c60000 c745d074944000 c745d480944000 8945d8 ff15???????? 8945cc }
            // n = 7, score = 200
            //   c745c43c000000       | mov                 dword ptr [ebp - 0x3c], 0x3c
            //   c745c840c60000       | mov                 dword ptr [ebp - 0x38], 0xc640
            //   c745d074944000       | mov                 dword ptr [ebp - 0x30], 0x409474
            //   c745d480944000       | mov                 dword ptr [ebp - 0x2c], 0x409480
            //   8945d8               | mov                 dword ptr [ebp - 0x28], eax
            //   ff15????????         |                     
            //   8945cc               | mov                 dword ptr [ebp - 0x34], eax

        $sequence_5 = { 0f88f5000000 395dfc 0f84ec000000 6804010000 8d85ccfdffff 50 ff15???????? }
            // n = 7, score = 200
            //   0f88f5000000         | js                  0xfb
            //   395dfc               | cmp                 dword ptr [ebp - 4], ebx
            //   0f84ec000000         | je                  0xf2
            //   6804010000           | push                0x104
            //   8d85ccfdffff         | lea                 eax, [ebp - 0x234]
            //   50                   | push                eax
            //   ff15????????         |                     

        $sequence_6 = { e8???????? 8b16 8b4e1c 8944d104 ff06 eb03 }
            // n = 6, score = 200
            //   e8????????           |                     
            //   8b16                 | mov                 edx, dword ptr [esi]
            //   8b4e1c               | mov                 ecx, dword ptr [esi + 0x1c]
            //   8944d104             | mov                 dword ptr [ecx + edx*8 + 4], eax
            //   ff06                 | inc                 dword ptr [esi]
            //   eb03                 | jmp                 5

        $sequence_7 = { 8d442418 50 ff742420 ff15???????? 85c0 7539 33db }
            // n = 7, score = 200
            //   8d442418             | lea                 eax, [esp + 0x18]
            //   50                   | push                eax
            //   ff742420             | push                dword ptr [esp + 0x20]
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7539                 | jne                 0x3b
            //   33db                 | xor                 ebx, ebx

        $sequence_8 = { e9???????? 6880000000 56 33ff ff15???????? 33c9 51 }
            // n = 7, score = 200
            //   e9????????           |                     
            //   6880000000           | push                0x80
            //   56                   | push                esi
            //   33ff                 | xor                 edi, edi
            //   ff15????????         |                     
            //   33c9                 | xor                 ecx, ecx
            //   51                   | push                ecx

        $sequence_9 = { 790f 51 ba???????? 8d4dfc e8???????? }
            // n = 5, score = 200
            //   790f                 | jns                 0x11
            //   51                   | push                ecx
            //   ba????????           |                     
            //   8d4dfc               | lea                 ecx, [ebp - 4]
            //   e8????????           |                     

    condition:
        7 of them and filesize < 131072
}

rule win_fuxsocy_w0 {
    meta:
        author = "Stephan Simon <stephan.simon@binarydefense.com>"
        date = "2019-10-24"
        description = "A ransomware tweeted about by @malwrhunterteam"
        modified = "2019-10-24"
        reference = "https://twitter.com/malwrhunterteam/status/1187360440734625798"
        tlp = "WHITE"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.fuxsocy"
        malpedia_version = "20191031"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    strings:
        $n1 = "FuxSocy_Evaluated" wide
        $n2 = "FuxSocy_InstallPlace" wide
        $n3 = "FuxSocy_Instance" wide
 
        $s1 = "{RAND}" wide
        $s2 = "\\x*x.exe" wide
        $s3 = "%.4d-%.2d-%.2dT%.2d:%.2d:%.2d" wide
        $s4 = "PT1M" wide
        $s5 = "PT0S" wide
        $s6 = "/d /c taskkill /f /pid %d > NUL & ping -n 1 127.0.0.1 > NUL & del \"%s\" > NUL & exit" wide
        $s7 = "/d /c start \"\" \"%s\"" wide
        $s8 = "Win32_ShadowCopy.ID='%s'" wide
        $s9 = "SuperHidden" wide
        $s10 = "ShowSuperHidden" wide
        $s11 = "Shell.IPC.%s" wide
        $s12 = "\\StringFileInfo\\%04x%04x\\%s" wide

    condition:
        filesize <= 100KB and
        (1 of ($n*) or 4 of ($s*))
}