rule win_biscuit_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        version = "1"
        description = "Detects win.biscuit."
        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.biscuit"
        malpedia_rule_date = "20230328"
        malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d"
        malpedia_version = "20230407"
        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 = { c745fc00000002 8bf0 b903000000 bf???????? 33c0 f3a6 7507 }
            // n = 7, score = 100
            //   c745fc00000002       | mov                 dword ptr [ebp - 4], 0x2000000
            //   8bf0                 | mov                 esi, eax
            //   b903000000           | mov                 ecx, 3
            //   bf????????           |                     
            //   33c0                 | xor                 eax, eax
            //   f3a6                 | repe cmpsb          byte ptr [esi], byte ptr es:[edi]
            //   7507                 | jne                 9

        $sequence_1 = { 8bfb 83c9ff 33c0 83c418 }
            // n = 4, score = 100
            //   8bfb                 | mov                 edi, ebx
            //   83c9ff               | or                  ecx, 0xffffffff
            //   33c0                 | xor                 eax, eax
            //   83c418               | add                 esp, 0x18

        $sequence_2 = { e8???????? 83c404 8945f0 b919000000 33c0 8b7df0 f3ab }
            // n = 7, score = 100
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   b919000000           | mov                 ecx, 0x19
            //   33c0                 | xor                 eax, eax
            //   8b7df0               | mov                 edi, dword ptr [ebp - 0x10]
            //   f3ab                 | rep stosd           dword ptr es:[edi], eax

        $sequence_3 = { 8d8c2410050000 51 8b8c2484020000 52 50 8d94241c030000 }
            // n = 6, score = 100
            //   8d8c2410050000       | lea                 ecx, [esp + 0x510]
            //   51                   | push                ecx
            //   8b8c2484020000       | mov                 ecx, dword ptr [esp + 0x284]
            //   52                   | push                edx
            //   50                   | push                eax
            //   8d94241c030000       | lea                 edx, [esp + 0x31c]

        $sequence_4 = { 8975f0 8975e4 8975fc 8975e8 e8???????? }
            // n = 5, score = 100
            //   8975f0               | mov                 dword ptr [ebp - 0x10], esi
            //   8975e4               | mov                 dword ptr [ebp - 0x1c], esi
            //   8975fc               | mov                 dword ptr [ebp - 4], esi
            //   8975e8               | mov                 dword ptr [ebp - 0x18], esi
            //   e8????????           |                     

        $sequence_5 = { 0f8547040000 6a02 68???????? b9???????? }
            // n = 4, score = 100
            //   0f8547040000         | jne                 0x44d
            //   6a02                 | push                2
            //   68????????           |                     
            //   b9????????           |                     

        $sequence_6 = { 898d04b8ffff 8b9504b8ffff 52 e8???????? 83c404 }
            // n = 5, score = 100
            //   898d04b8ffff         | mov                 dword ptr [ebp - 0x47fc], ecx
            //   8b9504b8ffff         | mov                 edx, dword ptr [ebp - 0x47fc]
            //   52                   | push                edx
            //   e8????????           |                     
            //   83c404               | add                 esp, 4

        $sequence_7 = { 89956c9fffff 8b856c9fffff 8a08 80e901 8b956c9fffff 880a }
            // n = 6, score = 100
            //   89956c9fffff         | mov                 dword ptr [ebp - 0x6094], edx
            //   8b856c9fffff         | mov                 eax, dword ptr [ebp - 0x6094]
            //   8a08                 | mov                 cl, byte ptr [eax]
            //   80e901               | sub                 cl, 1
            //   8b956c9fffff         | mov                 edx, dword ptr [ebp - 0x6094]
            //   880a                 | mov                 byte ptr [edx], cl

        $sequence_8 = { 33c0 8a42ff 85c0 7410 8b4de4 33d2 }
            // n = 6, score = 100
            //   33c0                 | xor                 eax, eax
            //   8a42ff               | mov                 al, byte ptr [edx - 1]
            //   85c0                 | test                eax, eax
            //   7410                 | je                  0x12
            //   8b4de4               | mov                 ecx, dword ptr [ebp - 0x1c]
            //   33d2                 | xor                 edx, edx

        $sequence_9 = { 7413 8b8d30fdffff 33d2 8a51ff 81faff000000 752f 8b8538fdffff }
            // n = 7, score = 100
            //   7413                 | je                  0x15
            //   8b8d30fdffff         | mov                 ecx, dword ptr [ebp - 0x2d0]
            //   33d2                 | xor                 edx, edx
            //   8a51ff               | mov                 dl, byte ptr [ecx - 1]
            //   81faff000000         | cmp                 edx, 0xff
            //   752f                 | jne                 0x31
            //   8b8538fdffff         | mov                 eax, dword ptr [ebp - 0x2c8]

    condition:
        7 of them and filesize < 180224
}