SYMBOLCOMMON_NAMEaka. SYNONYMS
win.yorekey (Back to overview)

YoreKey

Actor(s): Kimsuky


There is no description at this point.

References
2021-11-18ProofpointDarien Huss, Selena Larson
@online{huss:20211118:triple:62c1c14, author = {Darien Huss and Selena Larson}, title = {{Triple Threat: North Korea-Aligned TA406 Scams, Spies, and Steals}}, date = {2021-11-18}, organization = {Proofpoint}, url = {https://www.proofpoint.com/us/blog/threat-insight/triple-threat-north-korea-aligned-ta406-scams-spies-and-steals}, language = {English}, urldate = {2021-12-15} } Triple Threat: North Korea-Aligned TA406 Scams, Spies, and Steals
YoreKey
2021-11-18ProofpointDarien Huss, Selena Larson
@techreport{huss:20211118:triple:dd07fa8, author = {Darien Huss and Selena Larson}, title = {{Triple Threat: North Korea-Aligned TA406 Steals, Scams and Spies}}, date = {2021-11-18}, institution = {Proofpoint}, url = {https://www.proofpoint.com/sites/default/files/threat-reports/pfpt-us-tr-threat-insight-paper-triple-threat-N-Korea-aligned-TA406-steals-scams-spies.pdf}, language = {English}, urldate = {2021-12-15} } Triple Threat: North Korea-Aligned TA406 Steals, Scams and Spies
YoreKey
Yara Rules
[TLP:WHITE] win_yorekey_auto (20230125 | Detects win.yorekey.)
rule win_yorekey_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.yorekey."
        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.yorekey"
        malpedia_rule_date = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 750a 85c0 7506 ff15???????? }
            // n = 4, score = 200
            //   750a                 | jne                 0xc
            //   85c0                 | test                eax, eax
            //   7506                 | jne                 8
            //   ff15????????         |                     

        $sequence_1 = { eb03 488bc7 44883c08 48895f10 48837f1810 7205 }
            // n = 6, score = 100
            //   eb03                 | and                 ecx, 0xf
            //   488bc7               | jmp                 5
            //   44883c08             | jmp                 5
            //   48895f10             | dec                 eax
            //   48837f1810           | mov                 eax, edi
            //   7205                 | inc                 esp

        $sequence_2 = { 490fbec7 420fbe8c08205e0100 83e10f eb03 }
            // n = 4, score = 100
            //   490fbec7             | dec                 ecx
            //   420fbe8c08205e0100     | movsx    eax, bh
            //   83e10f               | inc                 edx
            //   eb03                 | movsx               ecx, byte ptr [eax + ecx + 0x15e20]

        $sequence_3 = { 56 8d957cffffff 57 52 e8???????? 8b7d8c }
            // n = 6, score = 100
            //   56                   | mov                 dword ptr [ebp - 0x10], eax
            //   8d957cffffff         | dec                 eax
            //   57                   | lea                 edx, [ebp - 0x60]
            //   52                   | dec                 eax
            //   e8????????           |                     
            //   8b7d8c               | lea                 ecx, [0x19fbd]

        $sequence_4 = { 488b05???????? 4833c4 488945f0 488d55a0 488d0dbd9f0100 }
            // n = 5, score = 100
            //   488b05????????       |                     
            //   4833c4               | xor                 eax, eax
            //   488945f0             | cmp                 cl, 0xa
            //   488d55a0             | sete                al
            //   488d0dbd9f0100       | mov                 dword ptr [esp + 0x44], eax

        $sequence_5 = { 7520 80fcfe 751b 6a02 }
            // n = 4, score = 100
            //   7520                 | mov                 dword ptr [ebp - 0x20], esi
            //   80fcfe               | lea                 esi, [ecx + 0x411530]
            //   751b                 | mov                 dword ptr [ebp - 0x1c], esi
            //   6a02                 | jmp                 0x39

        $sequence_6 = { 55 8bec 8b4508 56 8d34c5d8194100 }
            // n = 5, score = 100
            //   55                   | jne                 8
            //   8bec                 | jb                  0x11
            //   8b4508               | mov                 edx, dword ptr [ebp - 0x84]
            //   56                   | push                edx
            //   8d34c5d8194100       | add                 esp, 4

        $sequence_7 = { 33c0 80f90a 0f94c0 89442444 488d05c00d0100 }
            // n = 5, score = 100
            //   33c0                 | nop                 
            //   80f90a               | dec                 eax
            //   0f94c0               | inc                 eax
            //   89442444             | cmp                 word ptr [ebx + eax*2], si
            //   488d05c00d0100       | test                eax, eax

        $sequence_8 = { 8b3d???????? bb04000000 6a0a ff15???????? ff15???????? 85c0 }
            // n = 6, score = 100
            //   8b3d????????         |                     
            //   bb04000000           | dec                 eax
            //   6a0a                 | lea                 eax, [0x10ce3]
            //   ff15????????         |                     
            //   ff15????????         |                     
            //   85c0                 | dec                 eax

        $sequence_9 = { 897c243c 897c2438 6689bc2480000000 e8???????? 488d942480000000 41b804010000 }
            // n = 6, score = 100
            //   897c243c             | je                  0x1d
            //   897c2438             | dec                 eax
            //   6689bc2480000000     | mov                 ecx, dword ptr [esp + 0x38]
            //   e8????????           |                     
            //   488d942480000000     | dec                 eax
            //   41b804010000         | lea                 edx, [0xf7ac]

        $sequence_10 = { 720f 8b957cffffff 52 e8???????? 83c404 8bc6 }
            // n = 6, score = 100
            //   720f                 | inc                 ecx
            //   8b957cffffff         | mov                 eax, 0x104
            //   52                   | dec                 eax
            //   e8????????           |                     
            //   83c404               | xor                 eax, esp
            //   8bc6                 | dec                 eax

        $sequence_11 = { 8d8d74ffffff 51 56 57 53 ff15???????? 85c0 }
            // n = 7, score = 100
            //   8d8d74ffffff         | mov                 eax, esi
            //   51                   | push                esi
            //   56                   | lea                 edx, [ebp - 0x84]
            //   57                   | push                edi
            //   53                   | push                edx
            //   ff15????????         |                     
            //   85c0                 | mov                 edi, dword ptr [ebp - 0x74]

        $sequence_12 = { 85c0 741b 488b4c2438 488d15acf70000 ff15???????? }
            // n = 5, score = 100
            //   85c0                 | jb                  7
            //   741b                 | jne                 0x3d
            //   488b4c2438           | dec                 eax
            //   488d15acf70000       | or                  eax, 0xffffffff
            //   ff15????????         |                     

        $sequence_13 = { 83c40c 6bc930 8975e0 8db130154100 8975e4 eb2b 8a4601 }
            // n = 7, score = 100
            //   83c40c               | mov                 ecx, dword ptr [eax + ecx*8]
            //   6bc930               | dec                 esp
            //   8975e0               | lea                 ecx, [esp + 0x58]
            //   8db130154100         | dec                 eax
            //   8975e4               | lea                 edx, [esp + 0x60]
            //   eb2b                 | jne                 0xc
            //   8a4601               | test                eax, eax

        $sequence_14 = { 753b 4883c8ff 90 48ffc0 66393443 }
            // n = 5, score = 100
            //   753b                 | mov                 byte ptr [eax + ecx], bh
            //   4883c8ff             | dec                 eax
            //   90                   | mov                 dword ptr [edi + 0x10], ebx
            //   48ffc0               | dec                 eax
            //   66393443             | cmp                 dword ptr [edi + 0x18], 0x10

    condition:
        7 of them and filesize < 274432
}
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