SYMBOLCOMMON_NAMEaka. SYNONYMS
win.knot (Back to overview)

Knot


Ransomware.

References
2021-01-02Twitter (MalwareHunterTeam)MalwareHunterTeam
@online{malwarehunterteam:20210102:knot:66922b6, author = {MalwareHunterTeam}, title = {{Tweet on Knot Ransomware}}, date = {2021-01-02}, organization = {Twitter (MalwareHunterTeam)}, url = {https://twitter.com/malwrhunterteam/status/1345313324825780226}, language = {English}, urldate = {2021-01-04} } Tweet on Knot Ransomware
Knot
Yara Rules
[TLP:WHITE] win_knot_auto (20220808 | Detects win.knot.)
rule win_knot_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        version = "1"
        description = "Detects win.knot."
        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.knot"
        malpedia_rule_date = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 6880000000 8d9580f7ffff 52 ff15???????? 8d8580f7ffff }
            // n = 5, score = 200
            //   6880000000           | push                0x80
            //   8d9580f7ffff         | lea                 edx, [ebp - 0x880]
            //   52                   | push                edx
            //   ff15????????         |                     
            //   8d8580f7ffff         | lea                 eax, [ebp - 0x880]

        $sequence_1 = { 51 ff15???????? 8945f4 837df400 7454 6a00 }
            // n = 6, score = 200
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   8945f4               | mov                 dword ptr [ebp - 0xc], eax
            //   837df400             | cmp                 dword ptr [ebp - 0xc], 0
            //   7454                 | je                  0x56
            //   6a00                 | push                0

        $sequence_2 = { ff15???????? 8b4d08 51 ff15???????? b001 8be5 5d }
            // n = 7, score = 200
            //   ff15????????         |                     
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   b001                 | mov                 al, 1
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp

        $sequence_3 = { 6a00 6a02 6a00 8b55e8 52 }
            // n = 5, score = 200
            //   6a00                 | push                0
            //   6a02                 | push                2
            //   6a00                 | push                0
            //   8b55e8               | mov                 edx, dword ptr [ebp - 0x18]
            //   52                   | push                edx

        $sequence_4 = { 8d95f8fdffff 52 e8???????? 83c408 898574f7ffff 83bd74f7ffff00 }
            // n = 6, score = 200
            //   8d95f8fdffff         | lea                 edx, [ebp - 0x208]
            //   52                   | push                edx
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   898574f7ffff         | mov                 dword ptr [ebp - 0x88c], eax
            //   83bd74f7ffff00       | cmp                 dword ptr [ebp - 0x88c], 0

        $sequence_5 = { 50 6a00 6a00 6a00 8b4df8 51 }
            // n = 6, score = 200
            //   50                   | push                eax
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   51                   | push                ecx

        $sequence_6 = { 83c414 6a00 8d95d0fdffff 52 8b45f8 50 8b8dd4fdffff }
            // n = 7, score = 200
            //   83c414               | add                 esp, 0x14
            //   6a00                 | push                0
            //   8d95d0fdffff         | lea                 edx, [ebp - 0x230]
            //   52                   | push                edx
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]
            //   50                   | push                eax
            //   8b8dd4fdffff         | mov                 ecx, dword ptr [ebp - 0x22c]

        $sequence_7 = { 85c0 753c 8b95e0feffff 52 6a00 6a01 }
            // n = 6, score = 200
            //   85c0                 | test                eax, eax
            //   753c                 | jne                 0x3e
            //   8b95e0feffff         | mov                 edx, dword ptr [ebp - 0x120]
            //   52                   | push                edx
            //   6a00                 | push                0
            //   6a01                 | push                1

        $sequence_8 = { e8???????? 83c408 68???????? 8b8d74f7ffff }
            // n = 4, score = 200
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   68????????           |                     
            //   8b8d74f7ffff         | mov                 ecx, dword ptr [ebp - 0x88c]

        $sequence_9 = { 83f801 750f 8d95f0fdffff 52 e8???????? }
            // n = 5, score = 200
            //   83f801               | cmp                 eax, 1
            //   750f                 | jne                 0x11
            //   8d95f0fdffff         | lea                 edx, [ebp - 0x210]
            //   52                   | push                edx
            //   e8????????           |                     

    condition:
        7 of them and filesize < 59392
}
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