SYMBOLCOMMON_NAMEaka. SYNONYMS
win.rektloader (Back to overview)

Rekt Loader


There is no description at this point.

References
2020-03-19PrevailionPrevailion
@online{prevailion:20200319:curious:082e652, author = {Prevailion}, title = {{The Curious Case of the Criminal Curriculum Vitae}}, date = {2020-03-19}, organization = {Prevailion}, url = {https://blog.prevailion.com/2020/03/the-curious-case-of-criminal-curriculum.html}, language = {English}, urldate = {2020-06-30} } The Curious Case of the Criminal Curriculum Vitae
LALALA Stealer NetSupportManager RAT Rekt Loader
Yara Rules
[TLP:WHITE] win_rektloader_auto (20221125 | Detects win.rektloader.)
rule win_rektloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-11-21"
        version = "1"
        description = "Detects win.rektloader."
        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.rektloader"
        malpedia_rule_date = "20221118"
        malpedia_hash = "e0702e2e6d1d00da65c8a29a4ebacd0a4c59e1af"
        malpedia_version = "20221125"
        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 = { e9???????? 8b45e4 8b0c8508ab5600 894dd4 8b55d4 81c2000e0000 }
            // n = 6, score = 100
            //   e9????????           |                     
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]
            //   8b0c8508ab5600       | mov                 ecx, dword ptr [eax*4 + 0x56ab08]
            //   894dd4               | mov                 dword ptr [ebp - 0x2c], ecx
            //   8b55d4               | mov                 edx, dword ptr [ebp - 0x2c]
            //   81c2000e0000         | add                 edx, 0xe00

        $sequence_1 = { e8???????? c645fc00 8d4de0 e8???????? 8b55e8 8955d4 c745fcffffffff }
            // n = 7, score = 100
            //   e8????????           |                     
            //   c645fc00             | mov                 byte ptr [ebp - 4], 0
            //   8d4de0               | lea                 ecx, [ebp - 0x20]
            //   e8????????           |                     
            //   8b55e8               | mov                 edx, dword ptr [ebp - 0x18]
            //   8955d4               | mov                 dword ptr [ebp - 0x2c], edx
            //   c745fcffffffff       | mov                 dword ptr [ebp - 4], 0xffffffff

        $sequence_2 = { 884dec 8d4dcc e8???????? c745fc00000000 0fbe5524 85d2 7510 }
            // n = 7, score = 100
            //   884dec               | mov                 byte ptr [ebp - 0x14], cl
            //   8d4dcc               | lea                 ecx, [ebp - 0x34]
            //   e8????????           |                     
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0
            //   0fbe5524             | movsx               edx, byte ptr [ebp + 0x24]
            //   85d2                 | test                edx, edx
            //   7510                 | jne                 0x12

        $sequence_3 = { 83bd6cffffff00 7432 8b8d74ffffff 8b9564ffffff 8a82f8f45200 8801 }
            // n = 6, score = 100
            //   83bd6cffffff00       | cmp                 dword ptr [ebp - 0x94], 0
            //   7432                 | je                  0x34
            //   8b8d74ffffff         | mov                 ecx, dword ptr [ebp - 0x8c]
            //   8b9564ffffff         | mov                 edx, dword ptr [ebp - 0x9c]
            //   8a82f8f45200         | mov                 al, byte ptr [edx + 0x52f4f8]
            //   8801                 | mov                 byte ptr [ecx], al

        $sequence_4 = { 52 8b45cc 50 e8???????? 83c404 50 8b4dd0 }
            // n = 7, score = 100
            //   52                   | push                edx
            //   8b45cc               | mov                 eax, dword ptr [ebp - 0x34]
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   50                   | push                eax
            //   8b4dd0               | mov                 ecx, dword ptr [ebp - 0x30]

        $sequence_5 = { 894598 8b4598 25c0010000 83f840 0f8491000000 eb12 }
            // n = 6, score = 100
            //   894598               | mov                 dword ptr [ebp - 0x68], eax
            //   8b4598               | mov                 eax, dword ptr [ebp - 0x68]
            //   25c0010000           | and                 eax, 0x1c0
            //   83f840               | cmp                 eax, 0x40
            //   0f8491000000         | je                  0x97
            //   eb12                 | jmp                 0x14

        $sequence_6 = { 8b450c 0fbe08 85c9 750f 33d2 8b4508 668910 }
            // n = 7, score = 100
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]
            //   0fbe08               | movsx               ecx, byte ptr [eax]
            //   85c9                 | test                ecx, ecx
            //   750f                 | jne                 0x11
            //   33d2                 | xor                 edx, edx
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   668910               | mov                 word ptr [eax], dx

        $sequence_7 = { ff15???????? 3305???????? b904000000 6bd118 898278995600 68???????? 8b45fc }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   3305????????         |                     
            //   b904000000           | mov                 ecx, 4
            //   6bd118               | imul                edx, ecx, 0x18
            //   898278995600         | mov                 dword ptr [edx + 0x569978], eax
            //   68????????           |                     
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]

        $sequence_8 = { 85d2 751b 8b4520 c70002000000 8b4d24 c70100000000 }
            // n = 6, score = 100
            //   85d2                 | test                edx, edx
            //   751b                 | jne                 0x1d
            //   8b4520               | mov                 eax, dword ptr [ebp + 0x20]
            //   c70002000000         | mov                 dword ptr [eax], 2
            //   8b4d24               | mov                 ecx, dword ptr [ebp + 0x24]
            //   c70100000000         | mov                 dword ptr [ecx], 0

        $sequence_9 = { 83ec54 a1???????? 33c5 8945fc 894dd4 8b45d4 83783800 }
            // n = 7, score = 100
            //   83ec54               | sub                 esp, 0x54
            //   a1????????           |                     
            //   33c5                 | xor                 eax, ebp
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   894dd4               | mov                 dword ptr [ebp - 0x2c], ecx
            //   8b45d4               | mov                 eax, dword ptr [ebp - 0x2c]
            //   83783800             | cmp                 dword ptr [eax + 0x38], 0

    condition:
        7 of them and filesize < 3080192
}
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