rule win_ufrstealer_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.ufrstealer."
        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.ufrstealer"
        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???????? ff35???????? ff15???????? 85c0 0f8471ecffff a3???????? 68???????? }
            // n = 7, score = 200
            //   68????????           |                     
            //   ff35????????         |                     
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f8471ecffff         | je                  0xffffec77
            //   a3????????           |                     
            //   68????????           |                     

        $sequence_1 = { a3???????? 68???????? ff15???????? 85c0 0f84b5e4ffff a3???????? 68???????? }
            // n = 7, score = 200
            //   a3????????           |                     
            //   68????????           |                     
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f84b5e4ffff         | je                  0xffffe4bb
            //   a3????????           |                     
            //   68????????           |                     

        $sequence_2 = { 85c0 7571 ff55e4 8945f0 85c0 7464 6a00 }
            // n = 7, score = 200
            //   85c0                 | test                eax, eax
            //   7571                 | jne                 0x73
            //   ff55e4               | call                dword ptr [ebp - 0x1c]
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   85c0                 | test                eax, eax
            //   7464                 | je                  0x66
            //   6a00                 | push                0

        $sequence_3 = { 0f84a3010000 83c019 8945e8 ff75e8 ff15???????? }
            // n = 5, score = 200
            //   0f84a3010000         | je                  0x1a9
            //   83c019               | add                 eax, 0x19
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   ff75e8               | push                dword ptr [ebp - 0x18]
            //   ff15????????         |                     

        $sequence_4 = { ff75fc ff15???????? 85c0 0f841d020000 a3???????? 68???????? }
            // n = 6, score = 200
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f841d020000         | je                  0x223
            //   a3????????           |                     
            //   68????????           |                     

        $sequence_5 = { ff75fc ff15???????? 85c0 0f846a020000 }
            // n = 4, score = 200
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   0f846a020000         | je                  0x270

        $sequence_6 = { 61 8b55f4 42 8955f4 3b55f0 0f82ddfcffff }
            // n = 6, score = 200
            //   61                   | popal               
            //   8b55f4               | mov                 edx, dword ptr [ebp - 0xc]
            //   42                   | inc                 edx
            //   8955f4               | mov                 dword ptr [ebp - 0xc], edx
            //   3b55f0               | cmp                 edx, dword ptr [ebp - 0x10]
            //   0f82ddfcffff         | jb                  0xfffffce3

        $sequence_7 = { 7405 e8???????? 8bc4 c3 33c0 c3 64a130000000 }
            // n = 7, score = 200
            //   7405                 | je                  7
            //   e8????????           |                     
            //   8bc4                 | mov                 eax, esp
            //   c3                   | ret                 
            //   33c0                 | xor                 eax, eax
            //   c3                   | ret                 
            //   64a130000000         | mov                 eax, dword ptr fs:[0x30]

        $sequence_8 = { 55 8bec 6a00 ff750c ff7508 ff15???????? 0bc0 }
            // n = 7, score = 200
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   6a00                 | push                0
            //   ff750c               | push                dword ptr [ebp + 0xc]
            //   ff7508               | push                dword ptr [ebp + 8]
            //   ff15????????         |                     
            //   0bc0                 | or                  eax, eax

        $sequence_9 = { 05???????? 59 8808 8b45f0 8945f4 59 49 }
            // n = 7, score = 200
            //   05????????           |                     
            //   59                   | pop                 ecx
            //   8808                 | mov                 byte ptr [eax], cl
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]
            //   8945f4               | mov                 dword ptr [ebp - 0xc], eax
            //   59                   | pop                 ecx
            //   49                   | dec                 ecx

    condition:
        7 of them and filesize < 770048
}