rule win_curlback_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.curlback."
        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.curlback"
        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 = { 83f801 750d 488d542468 488bce e8???????? 4c8b742468 4d85f6 }
            // n = 7, score = 100
            //   83f801               | dec                 eax
            //   750d                 | mov                 ecx, ebx
            //   488d542468           | mov                 eax, 2
            //   488bce               | inc                 eax
            //   e8????????           |                     
            //   4c8b742468           | cmp                 byte ptr [ecx + 0x25e], ch
            //   4d85f6               | jne                 0x17eb

        $sequence_1 = { 90 488d4c2430 e8???????? 488b4d38 488b01 ff5010 }
            // n = 6, score = 100
            //   90                   | je                  0x1d5b
            //   488d4c2430           | dec                 eax
            //   e8????????           |                     
            //   488b4d38             | lea                 edx, [0xb8ce1]
            //   488b01               | mov                 edi, eax
            //   ff5010               | dec                 eax

        $sequence_2 = { ba2d270000 488b09 e8???????? 488b4f18 baac000000 41b801000000 488b09 }
            // n = 7, score = 100
            //   ba2d270000           | dec                 ecx
            //   488b09               | mov                 dword ptr [ebx - 0x38], eax
            //   e8????????           |                     
            //   488b4f18             | dec                 ebp
            //   baac000000           | lea                 ecx, [ebx - 0x18]
            //   41b801000000         | inc                 ecx
            //   488b09               | mov                 eax, 1

        $sequence_3 = { 7410 4883f802 7411 bb2b000000 e9???????? 488d3d2e9b0900 493bd1 }
            // n = 7, score = 100
            //   7410                 | lea                 ecx, [ebp + 0x710]
            //   4883f802             | dec                 esp
            //   7411                 | arpl                ax, ax
            //   bb2b000000           | dec                 esp
            //   e9????????           |                     
            //   488d3d2e9b0900       | lea                 ecx, [ebp + 0x5d0]
            //   493bd1               | dec                 esp

        $sequence_4 = { e8???????? b823000000 eb14 488d152db00b00 488bce e8???????? b84d000000 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   b823000000           | lea                 ecx, [esp + 0x20]
            //   eb14                 | movups              xmmword ptr [edx], xmm0
            //   488d152db00b00       | dec                 eax
            //   488bce               | lea                 eax, [0xe7373]
            //   e8????????           |                     
            //   b84d000000           | dec                 eax

        $sequence_5 = { 791b ff15???????? 488d1579470d00 448bc8 4c8bc7 488bce e8???????? }
            // n = 7, score = 100
            //   791b                 | mov                 ecx, ebx
            //   ff15????????         |                     
            //   488d1579470d00       | mov                 dword ptr [esi + 0xa8], 2
            //   448bc8               | dec                 esp
            //   4c8bc7               | lea                 esi, [esi + 0xa8]
            //   488bce               | je                  0x6fb
            //   e8????????           |                     

        $sequence_6 = { 4863f8 4c8d35f5170f00 488bcb 48c1ff06 e8???????? 83e03f 488d14c0 }
            // n = 7, score = 100
            //   4863f8               | mov                 ecx, edi
            //   4c8d35f5170f00       | dec                 eax
            //   488bcb               | cmova               eax, dword ptr [ebp + 0x120]
            //   48c1ff06             | dec                 eax
            //   e8????????           |                     
            //   83e03f               | mov                 dword ptr [esp + 0x30], ecx
            //   488d14c0             | dec                 eax

        $sequence_7 = { 742f 80bb1f13000000 7526 488d542420 0f1f840000000000 0fb60a 488d5201 }
            // n = 7, score = 100
            //   742f                 | dec                 eax
            //   80bb1f13000000       | mov                 esi, edx
            //   7526                 | push                edi
            //   488d542420           | inc                 ecx
            //   0f1f840000000000     | push                esi
            //   0fb60a               | inc                 ecx
            //   488d5201             | push                edi

        $sequence_8 = { e8???????? 90 488d4de8 e8???????? 90 bb00100000 488b55c0 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   90                   | dec                 ecx
            //   488d4de8             | sub                 esi, esi
            //   e8????????           |                     
            //   90                   | dec                 ecx
            //   bb00100000           | mov                 eax, edi
            //   488b55c0             | dec                 ecx

        $sequence_9 = { 7505 49893e eb03 48893e ff8d00020000 488b4b28 ff15???????? }
            // n = 7, score = 100
            //   7505                 | inc                 ecx
            //   49893e               | lea                 ecx, [ebp + 0x101]
            //   eb03                 | inc                 sp
            //   48893e               | mov                 dword ptr [eax + 0x170c], ecx
            //   ff8d00020000         | jmp                 0x1e
            //   488b4b28             | lea                 ecx, [edx + ebx]
            //   ff15????????         |                     

    condition:
        7 of them and filesize < 4027392
}