rule win_tendyron_dropper_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.tendyron_dropper."
        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.tendyron_dropper"
        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 = { 68???????? 53 53 891d???????? 895de8 ff15???????? }
            // n = 6, score = 100
            //   68????????           |                     
            //   53                   | push                ebx
            //   53                   | push                ebx
            //   891d????????         |                     
            //   895de8               | mov                 dword ptr [ebp - 0x18], ebx
            //   ff15????????         |                     

        $sequence_1 = { 0145f8 6a00 6a04 8d45f8 }
            // n = 4, score = 100
            //   0145f8               | add                 dword ptr [ebp - 8], eax
            //   6a00                 | push                0
            //   6a04                 | push                4
            //   8d45f8               | lea                 eax, [ebp - 8]

        $sequence_2 = { 50 ff15???????? 8bd8 85db 74ea 6a18 }
            // n = 6, score = 100
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8bd8                 | mov                 ebx, eax
            //   85db                 | test                ebx, ebx
            //   74ea                 | je                  0xffffffec
            //   6a18                 | push                0x18

        $sequence_3 = { 4e 75f4 8d45d8 50 57 }
            // n = 5, score = 100
            //   4e                   | dec                 esi
            //   75f4                 | jne                 0xfffffff6
            //   8d45d8               | lea                 eax, [ebp - 0x28]
            //   50                   | push                eax
            //   57                   | push                edi

        $sequence_4 = { 66894598 8d459a 81e6ffffff7f 037578 50 e8???????? }
            // n = 6, score = 100
            //   66894598             | mov                 word ptr [ebp - 0x68], ax
            //   8d459a               | lea                 eax, [ebp - 0x66]
            //   81e6ffffff7f         | and                 esi, 0x7fffffff
            //   037578               | add                 esi, dword ptr [ebp + 0x78]
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_5 = { 85c0 7506 0fb7c7 89457c 8b7d7c }
            // n = 5, score = 100
            //   85c0                 | test                eax, eax
            //   7506                 | jne                 8
            //   0fb7c7               | movzx               eax, di
            //   89457c               | mov                 dword ptr [ebp + 0x7c], eax
            //   8b7d7c               | mov                 edi, dword ptr [ebp + 0x7c]

        $sequence_6 = { 399decfdffff 7420 68???????? ffb5ecfdffff e8???????? 59 59 }
            // n = 7, score = 100
            //   399decfdffff         | cmp                 dword ptr [ebp - 0x214], ebx
            //   7420                 | je                  0x22
            //   68????????           |                     
            //   ffb5ecfdffff         | push                dword ptr [ebp - 0x214]
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   59                   | pop                 ecx

        $sequence_7 = { ff75d4 ffd0 85c0 0f85fc010000 8b45f4 6a40 6800300000 }
            // n = 7, score = 100
            //   ff75d4               | push                dword ptr [ebp - 0x2c]
            //   ffd0                 | call                eax
            //   85c0                 | test                eax, eax
            //   0f85fc010000         | jne                 0x202
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   6a40                 | push                0x40
            //   6800300000           | push                0x3000

        $sequence_8 = { eb04 32c2 02c2 8801 41 4e }
            // n = 6, score = 100
            //   eb04                 | jmp                 6
            //   32c2                 | xor                 al, dl
            //   02c2                 | add                 al, dl
            //   8801                 | mov                 byte ptr [ecx], al
            //   41                   | inc                 ecx
            //   4e                   | dec                 esi

        $sequence_9 = { ff15???????? 85c0 0f84b0010000 33c0 8945f8 394714 }
            // n = 6, score = 100
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f84b0010000         | je                  0x1b6
            //   33c0                 | xor                 eax, eax
            //   8945f8               | mov                 dword ptr [ebp - 8], eax
            //   394714               | cmp                 dword ptr [edi + 0x14], eax

    condition:
        7 of them and filesize < 58368
}

rule win_tendyron_dropper_w0 {
    meta:       
        description = "TA410 Tendyron Dropper"
        reference = "https://www.welivesecurity.com/"
        source = "https://github.com/eset/malware-ioc/"
        license = "BSD 2-Clause"
        version = "1"
        author = "ESET Research"
        date = "2020-12-09"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.tendyron_dropper"
        malpedia_rule_date = "20251015"
        malpedia_hash = ""
        malpedia_version = "20251015"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $s1 = "Global\\{F473B3BE-08EE-4710-A727-9E248F804F4A}" wide
        $s2 = "Global\\8D32CCB321B2" wide
        $s3 = "Global\\E4FE94F75490" wide
        $s4 = "Program Files (x86)\\Internet Explorer\\iexplore.exe" wide
        $s5 = "\\RPC Control\\OLE" wide
        $s6 = "ALPC Port" wide
    condition:
        int16(0) == 0x5A4D and 4 of them
}