rule win_synccrypt_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.synccrypt."
        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.synccrypt"
        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 = { 8b4108 3b410c 0f83c3040000 0fb600 8b4d10 89450c 85c9 }
            // n = 7, score = 100
            //   8b4108               | mov                 eax, dword ptr [ecx + 8]
            //   3b410c               | cmp                 eax, dword ptr [ecx + 0xc]
            //   0f83c3040000         | jae                 0x4c9
            //   0fb600               | movzx               eax, byte ptr [eax]
            //   8b4d10               | mov                 ecx, dword ptr [ebp + 0x10]
            //   89450c               | mov                 dword ptr [ebp + 0xc], eax
            //   85c9                 | test                ecx, ecx

        $sequence_1 = { c7042422000000 e8???????? e9???????? e8???????? 85c0 89c3 0f8481000000 }
            // n = 7, score = 100
            //   c7042422000000       | mov                 dword ptr [esp], 0x22
            //   e8????????           |                     
            //   e9????????           |                     
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   89c3                 | mov                 ebx, eax
            //   0f8481000000         | je                  0x87

        $sequence_2 = { c7042400000000 89442408 8d442434 89542434 89442404 e8???????? 85c0 }
            // n = 7, score = 100
            //   c7042400000000       | mov                 dword ptr [esp], 0
            //   89442408             | mov                 dword ptr [esp + 8], eax
            //   8d442434             | lea                 eax, [esp + 0x34]
            //   89542434             | mov                 dword ptr [esp + 0x34], edx
            //   89442404             | mov                 dword ptr [esp + 4], eax
            //   e8????????           |                     
            //   85c0                 | test                eax, eax

        $sequence_3 = { c744243801000000 c744243c20000000 e9???????? 8b5c2410 85db 7439 8b74242c }
            // n = 7, score = 100
            //   c744243801000000     | mov                 dword ptr [esp + 0x38], 1
            //   c744243c20000000     | mov                 dword ptr [esp + 0x3c], 0x20
            //   e9????????           |                     
            //   8b5c2410             | mov                 ebx, dword ptr [esp + 0x10]
            //   85db                 | test                ebx, ebx
            //   7439                 | je                  0x3b
            //   8b74242c             | mov                 esi, dword ptr [esp + 0x2c]

        $sequence_4 = { e8???????? 8b442428 8b54242c c7431000000000 c7430c00000000 894308 8b4314 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   8b442428             | mov                 eax, dword ptr [esp + 0x28]
            //   8b54242c             | mov                 edx, dword ptr [esp + 0x2c]
            //   c7431000000000       | mov                 dword ptr [ebx + 0x10], 0
            //   c7430c00000000       | mov                 dword ptr [ebx + 0xc], 0
            //   894308               | mov                 dword ptr [ebx + 8], eax
            //   8b4314               | mov                 eax, dword ptr [ebx + 0x14]

        $sequence_5 = { c1f803 29c2 7246 8b44245c 8b4c245c 8d1c17 01f8 }
            // n = 7, score = 100
            //   c1f803               | sar                 eax, 3
            //   29c2                 | sub                 edx, eax
            //   7246                 | jb                  0x48
            //   8b44245c             | mov                 eax, dword ptr [esp + 0x5c]
            //   8b4c245c             | mov                 ecx, dword ptr [esp + 0x5c]
            //   8d1c17               | lea                 ebx, [edi + edx]
            //   01f8                 | add                 eax, edi

        $sequence_6 = { ffd7 85c0 75be 83c43c b8ffffffff 5b 5e }
            // n = 7, score = 100
            //   ffd7                 | call                edi
            //   85c0                 | test                eax, eax
            //   75be                 | jne                 0xffffffc0
            //   83c43c               | add                 esp, 0x3c
            //   b8ffffffff           | mov                 eax, 0xffffffff
            //   5b                   | pop                 ebx
            //   5e                   | pop                 esi

        $sequence_7 = { f60001 7545 895c2404 891c24 e8???????? 85c0 74d1 }
            // n = 7, score = 100
            //   f60001               | test                byte ptr [eax], 1
            //   7545                 | jne                 0x47
            //   895c2404             | mov                 dword ptr [esp + 4], ebx
            //   891c24               | mov                 dword ptr [esp], ebx
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   74d1                 | je                  0xffffffd3

        $sequence_8 = { e8???????? 896c2404 890424 89c7 e8???????? 85c0 7411 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   896c2404             | mov                 dword ptr [esp + 4], ebp
            //   890424               | mov                 dword ptr [esp], eax
            //   89c7                 | mov                 edi, eax
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   7411                 | je                  0x13

        $sequence_9 = { c70100000000 e9???????? c7442408???????? c74424045c010000 c70424???????? e8???????? e9???????? }
            // n = 7, score = 100
            //   c70100000000         | mov                 dword ptr [ecx], 0
            //   e9????????           |                     
            //   c7442408????????     |                     
            //   c74424045c010000     | mov                 dword ptr [esp + 4], 0x15c
            //   c70424????????       |                     
            //   e8????????           |                     
            //   e9????????           |                     

    condition:
        7 of them and filesize < 4489216
}