SYMBOLCOMMON_NAMEaka. SYNONYMS
win.gibberish (Back to overview)

Gibberish


Ransomware.

References
2020-02-17ID RansomwareAndrew Ivanov
@online{ivanov:20200217:gibberish:b003dbc, author = {Andrew Ivanov}, title = {{Gibberish Ransomware}}, date = {2020-02-17}, organization = {ID Ransomware}, url = {https://id-ransomware.blogspot.com/2020/02/gibberish-ransomware.html}, language = {Russian}, urldate = {2020-03-22} } Gibberish Ransomware
Gibberish
Yara Rules
[TLP:WHITE] win_gibberish_auto (20230715 | Detects win.gibberish.)
rule win_gibberish_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.gibberish."
        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.gibberish"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { 83c10c e9???????? 8b4de0 83c11c e9???????? 8b4de0 83c144 }
            // n = 7, score = 100
            //   83c10c               | add                 ecx, 0xc
            //   e9????????           |                     
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]
            //   83c11c               | add                 ecx, 0x1c
            //   e9????????           |                     
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]
            //   83c144               | add                 ecx, 0x44

        $sequence_1 = { 3334c5f3a94700 8bc2 c1e810 0fb6c0 0fb688c8a94500 8bc2 }
            // n = 6, score = 100
            //   3334c5f3a94700       | xor                 esi, dword ptr [eax*8 + 0x47a9f3]
            //   8bc2                 | mov                 eax, edx
            //   c1e810               | shr                 eax, 0x10
            //   0fb6c0               | movzx               eax, al
            //   0fb688c8a94500       | movzx               ecx, byte ptr [eax + 0x45a9c8]
            //   8bc2                 | mov                 eax, edx

        $sequence_2 = { 33c8 8bc6 c1c806 33c8 8b442424 33442428 }
            // n = 6, score = 100
            //   33c8                 | xor                 ecx, eax
            //   8bc6                 | mov                 eax, esi
            //   c1c806               | ror                 eax, 6
            //   33c8                 | xor                 ecx, eax
            //   8b442424             | mov                 eax, dword ptr [esp + 0x24]
            //   33442428             | xor                 eax, dword ptr [esp + 0x28]

        $sequence_3 = { 53 8bd9 895c2404 57 c703???????? 83f808 }
            // n = 6, score = 100
            //   53                   | push                ebx
            //   8bd9                 | mov                 ebx, ecx
            //   895c2404             | mov                 dword ptr [esp + 4], ebx
            //   57                   | push                edi
            //   c703????????         |                     
            //   83f808               | cmp                 eax, 8

        $sequence_4 = { 8d45b0 50 e8???????? 83c404 ff7768 8d4dc8 }
            // n = 6, score = 100
            //   8d45b0               | lea                 eax, [ebp - 0x50]
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   ff7768               | push                dword ptr [edi + 0x68]
            //   8d4dc8               | lea                 ecx, [ebp - 0x38]

        $sequence_5 = { 80f939 0f8f9a050000 0fbe46ff ff348508ad4500 }
            // n = 4, score = 100
            //   80f939               | cmp                 cl, 0x39
            //   0f8f9a050000         | jg                  0x5a0
            //   0fbe46ff             | movsx               eax, byte ptr [esi - 1]
            //   ff348508ad4500       | push                dword ptr [eax*4 + 0x45ad08]

        $sequence_6 = { 8955b8 894db0 8975b4 85c0 7514 68???????? }
            // n = 6, score = 100
            //   8955b8               | mov                 dword ptr [ebp - 0x48], edx
            //   894db0               | mov                 dword ptr [ebp - 0x50], ecx
            //   8975b4               | mov                 dword ptr [ebp - 0x4c], esi
            //   85c0                 | test                eax, eax
            //   7514                 | jne                 0x16
            //   68????????           |                     

        $sequence_7 = { 83c30c c645fc01 817b0455555505 8b3b 0f8493000000 8b4704 8945e8 }
            // n = 7, score = 100
            //   83c30c               | add                 ebx, 0xc
            //   c645fc01             | mov                 byte ptr [ebp - 4], 1
            //   817b0455555505       | cmp                 dword ptr [ebx + 4], 0x5555555
            //   8b3b                 | mov                 edi, dword ptr [ebx]
            //   0f8493000000         | je                  0x99
            //   8b4704               | mov                 eax, dword ptr [edi + 4]
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax

        $sequence_8 = { 8b7508 6a0a 50 8d4590 898d78ffffff 50 c7458c00000000 }
            // n = 7, score = 100
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]
            //   6a0a                 | push                0xa
            //   50                   | push                eax
            //   8d4590               | lea                 eax, [ebp - 0x70]
            //   898d78ffffff         | mov                 dword ptr [ebp - 0x88], ecx
            //   50                   | push                eax
            //   c7458c00000000       | mov                 dword ptr [ebp - 0x74], 0

        $sequence_9 = { 660fdbd9 660fdbe1 f30f7ef6 0f28cd 660fdbf2 b802000000 0f28542440 }
            // n = 7, score = 100
            //   660fdbd9             | pand                xmm3, xmm1
            //   660fdbe1             | pand                xmm4, xmm1
            //   f30f7ef6             | movq                xmm6, xmm6
            //   0f28cd               | movaps              xmm1, xmm5
            //   660fdbf2             | pand                xmm6, xmm2
            //   b802000000           | mov                 eax, 2
            //   0f28542440           | movaps              xmm2, xmmword ptr [esp + 0x40]

    condition:
        7 of them and filesize < 1068032
}
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