rule win_zeus_mailsniffer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.zeus_mailsniffer."
        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.zeus_mailsniffer"
        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 = { 8b44cde8 a3???????? b001 5f 5e }
            // n = 5, score = 100
            //   8b44cde8             | mov                 eax, dword ptr [ebp + ecx*8 - 0x18]
            //   a3????????           |                     
            //   b001                 | mov                 al, 1
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_1 = { 57 b800070484 7405 b800074484 894dfc 8365fc04 7405 }
            // n = 7, score = 100
            //   57                   | push                edi
            //   b800070484           | mov                 eax, 0x84040700
            //   7405                 | je                  7
            //   b800074484           | mov                 eax, 0x84440700
            //   894dfc               | mov                 dword ptr [ebp - 4], ecx
            //   8365fc04             | and                 dword ptr [ebp - 4], 4
            //   7405                 | je                  7

        $sequence_2 = { 66837ddc00 8b87a0902d01 7403 6a29 58 8d8dd4fdffff 51 }
            // n = 7, score = 100
            //   66837ddc00           | cmp                 word ptr [ebp - 0x24], 0
            //   8b87a0902d01         | mov                 eax, dword ptr [edi + 0x12d90a0]
            //   7403                 | je                  5
            //   6a29                 | push                0x29
            //   58                   | pop                 eax
            //   8d8dd4fdffff         | lea                 ecx, [ebp - 0x22c]
            //   51                   | push                ecx

        $sequence_3 = { 8bf8 85ff 744a 83650800 85db 7435 83c608 }
            // n = 7, score = 100
            //   8bf8                 | mov                 edi, eax
            //   85ff                 | test                edi, edi
            //   744a                 | je                  0x4c
            //   83650800             | and                 dword ptr [ebp + 8], 0
            //   85db                 | test                ebx, ebx
            //   7435                 | je                  0x37
            //   83c608               | add                 esi, 8

        $sequence_4 = { 8bec 81ec1c050000 53 56 8d85f0fcffff 57 33db }
            // n = 7, score = 100
            //   8bec                 | mov                 ebp, esp
            //   81ec1c050000         | sub                 esp, 0x51c
            //   53                   | push                ebx
            //   56                   | push                esi
            //   8d85f0fcffff         | lea                 eax, [ebp - 0x310]
            //   57                   | push                edi
            //   33db                 | xor                 ebx, ebx

        $sequence_5 = { 50 68???????? 6815010000 53 }
            // n = 4, score = 100
            //   50                   | push                eax
            //   68????????           |                     
            //   6815010000           | push                0x115
            //   53                   | push                ebx

        $sequence_6 = { 8d8424a8070000 50 e8???????? 59 3bc3 }
            // n = 5, score = 100
            //   8d8424a8070000       | lea                 eax, [esp + 0x7a8]
            //   50                   | push                eax
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   3bc3                 | cmp                 eax, ebx

        $sequence_7 = { 0f8425010000 395df4 0f841c010000 e8???????? }
            // n = 4, score = 100
            //   0f8425010000         | je                  0x12b
            //   395df4               | cmp                 dword ptr [ebp - 0xc], ebx
            //   0f841c010000         | je                  0x122
            //   e8????????           |                     

        $sequence_8 = { ff75f0 8945e4 ffd6 68???????? ff75f0 8945d8 }
            // n = 6, score = 100
            //   ff75f0               | push                dword ptr [ebp - 0x10]
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax
            //   ffd6                 | call                esi
            //   68????????           |                     
            //   ff75f0               | push                dword ptr [ebp - 0x10]
            //   8945d8               | mov                 dword ptr [ebp - 0x28], eax

        $sequence_9 = { eb70 a80c 7464 8505???????? 745c 8d45e0 50 }
            // n = 7, score = 100
            //   eb70                 | jmp                 0x72
            //   a80c                 | test                al, 0xc
            //   7464                 | je                  0x66
            //   8505????????         |                     
            //   745c                 | je                  0x5e
            //   8d45e0               | lea                 eax, [ebp - 0x20]
            //   50                   | push                eax

    condition:
        7 of them and filesize < 368640
}