SYMBOLCOMMON_NAMEaka. SYNONYMS
win.nachocheese (Back to overview)

NACHOCHEESE

aka: Cyruslish, TWOPENCE, VIVACIOUSGIFT

Actor(s): Lazarus Group


According to FireEye, NACHOCHEESE is a command-line tunneler that accepts delimited C&C IPs or domains via command-line and gives actors shell access to a victim's system.

References
2020-08-26CISACISA
@online{cisa:20200826:mar103017062v1:e64b3ac, author = {CISA}, title = {{MAR-10301706-2.v1 - North Korean Remote Access Tool: VIVACIOUSGIFT}}, date = {2020-08-26}, organization = {CISA}, url = {https://us-cert.cisa.gov/ncas/analysis-reports/ar20-239b}, language = {English}, urldate = {2020-09-01} } MAR-10301706-2.v1 - North Korean Remote Access Tool: VIVACIOUSGIFT
NACHOCHEESE
2020-02-19LexfoLexfo
@techreport{lexfo:20200219:lazarus:f293c37, author = {Lexfo}, title = {{The Lazarus Constellation A study on North Korean malware}}, date = {2020-02-19}, institution = {Lexfo}, url = {https://blog.lexfo.fr/ressources/Lexfo-WhitePaper-The_Lazarus_Constellation.pdf}, language = {English}, urldate = {2020-03-11} } The Lazarus Constellation A study on North Korean malware
FastCash AppleJeus BADCALL Bankshot Brambul Dtrack Duuzer DYEPACK ELECTRICFISH HARDRAIN Hermes HOPLIGHT Joanap KEYMARBLE Kimsuky MimiKatz MyDoom NACHOCHEESE NavRAT PowerRatankba RokRAT Sierra(Alfa,Bravo, ...) Volgmer WannaCryptor
2018FireEyeFireEye
@techreport{fireeye:2018:apt38:c81b87d, author = {FireEye}, title = {{APT38}}, date = {2018}, institution = {FireEye}, url = {https://www.fireeye.com/content/dam/fireeye-www/current-threats/pdfs/pf/apt/rpt-apt38-2018.pdf}, language = {English}, urldate = {2020-01-07} } APT38
CHEESETRAY CLEANTOAD NACHOCHEESE
2017-02-20BAE SystemsSergei Shevchenko
@online{shevchenko:20170220:lazarus:c608fd5, author = {Sergei Shevchenko}, title = {{Lazarus’ False Flag Malware}}, date = {2017-02-20}, organization = {BAE Systems}, url = {https://baesystemsai.blogspot.com/2017/02/lazarus-false-flag-malware.html}, language = {English}, urldate = {2019-12-20} } Lazarus’ False Flag Malware
NACHOCHEESE
2017-02-16ESET ResearchPeter Kálnai
@online{klnai:20170216:demystifying:7ae8785, author = {Peter Kálnai}, title = {{Demystifying targeted malware used against Polish banks}}, date = {2017-02-16}, organization = {ESET Research}, url = {https://www.welivesecurity.com/2017/02/16/demystifying-targeted-malware-used-polish-banks/}, language = {English}, urldate = {2019-11-14} } Demystifying targeted malware used against Polish banks
HOTWAX NACHOCHEESE
Yara Rules
[TLP:WHITE] win_nachocheese_auto (20221125 | Detects win.nachocheese.)
rule win_nachocheese_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-11-21"
        version = "1"
        description = "Detects win.nachocheese."
        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.nachocheese"
        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 = { 02ca 880c3e 8a5005 32d1 8b4dfc 88143e }
            // n = 6, score = 300
            //   02ca                 | add                 cl, dl
            //   880c3e               | mov                 byte ptr [esi + edi], cl
            //   8a5005               | mov                 dl, byte ptr [eax + 5]
            //   32d1                 | xor                 dl, cl
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   88143e               | mov                 byte ptr [esi + edi], dl

        $sequence_1 = { 33c0 c3 05d13fffff 83f801 }
            // n = 4, score = 300
            //   33c0                 | xor                 eax, eax
            //   c3                   | ret                 
            //   05d13fffff           | add                 eax, 0xffff3fd1
            //   83f801               | cmp                 eax, 1

        $sequence_2 = { 2bfa 8d47fd 3901 8901 }
            // n = 4, score = 300
            //   2bfa                 | sub                 edi, edx
            //   8d47fd               | lea                 eax, [edi - 3]
            //   3901                 | cmp                 dword ptr [ecx], eax
            //   8901                 | mov                 dword ptr [ecx], eax

        $sequence_3 = { 33c8 894710 8b4708 33c1 }
            // n = 4, score = 300
            //   33c8                 | xor                 ecx, eax
            //   894710               | mov                 dword ptr [edi + 0x10], eax
            //   8b4708               | mov                 eax, dword ptr [edi + 8]
            //   33c1                 | xor                 eax, ecx

        $sequence_4 = { 8b0d???????? 8d950cffffff 6a00 52 }
            // n = 4, score = 300
            //   8b0d????????         |                     
            //   8d950cffffff         | lea                 edx, [ebp - 0xf4]
            //   6a00                 | push                0
            //   52                   | push                edx

        $sequence_5 = { 3d9c000000 7c07 3d9f000000 7e0d }
            // n = 4, score = 300
            //   3d9c000000           | cmp                 eax, 0x9c
            //   7c07                 | jl                  9
            //   3d9f000000           | cmp                 eax, 0x9f
            //   7e0d                 | jle                 0xf

        $sequence_6 = { 40 8945fc 83f802 0f8cfafeffff e8???????? 8b4704 5f }
            // n = 7, score = 300
            //   40                   | inc                 eax
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   83f802               | cmp                 eax, 2
            //   0f8cfafeffff         | jl                  0xffffff00
            //   e8????????           |                     
            //   8b4704               | mov                 eax, dword ptr [edi + 4]
            //   5f                   | pop                 edi

        $sequence_7 = { 7305 83c304 eb0f 81fb00000001 }
            // n = 4, score = 300
            //   7305                 | jae                 7
            //   83c304               | add                 ebx, 4
            //   eb0f                 | jmp                 0x11
            //   81fb00000001         | cmp                 ebx, 0x1000000

        $sequence_8 = { 52 8945f0 895dfc 895df8 ff15???????? 85c0 7408 }
            // n = 7, score = 300
            //   52                   | push                edx
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   895dfc               | mov                 dword ptr [ebp - 4], ebx
            //   895df8               | mov                 dword ptr [ebp - 8], ebx
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7408                 | je                  0xa

        $sequence_9 = { 3d2cc00000 7f18 3d2bc00000 7d1b 3d9c000000 }
            // n = 5, score = 300
            //   3d2cc00000           | cmp                 eax, 0xc02c
            //   7f18                 | jg                  0x1a
            //   3d2bc00000           | cmp                 eax, 0xc02b
            //   7d1b                 | jge                 0x1d
            //   3d9c000000           | cmp                 eax, 0x9c

        $sequence_10 = { c745e068007300 c745e468006400 c745e86e005a00 c745ec58006e00 c745f069006f00 c745f468007300 }
            // n = 6, score = 300
            //   c745e068007300       | mov                 dword ptr [ebp - 0x20], 0x730068
            //   c745e468006400       | mov                 dword ptr [ebp - 0x1c], 0x640068
            //   c745e86e005a00       | mov                 dword ptr [ebp - 0x18], 0x5a006e
            //   c745ec58006e00       | mov                 dword ptr [ebp - 0x14], 0x6e0058
            //   c745f069006f00       | mov                 dword ptr [ebp - 0x10], 0x6f0069
            //   c745f468007300       | mov                 dword ptr [ebp - 0xc], 0x730068

        $sequence_11 = { 52 ff15???????? 83f801 754b 8b450c }
            // n = 5, score = 300
            //   52                   | push                edx
            //   ff15????????         |                     
            //   83f801               | cmp                 eax, 1
            //   754b                 | jne                 0x4d
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]

        $sequence_12 = { 3d9f000000 7e0d 33c0 c3 }
            // n = 4, score = 300
            //   3d9f000000           | cmp                 eax, 0x9f
            //   7e0d                 | jle                 0xf
            //   33c0                 | xor                 eax, eax
            //   c3                   | ret                 

        $sequence_13 = { 8a540205 32d1 8b4df4 88143e 8a4c0105 02ca 8b55f4 }
            // n = 7, score = 300
            //   8a540205             | mov                 dl, byte ptr [edx + eax + 5]
            //   32d1                 | xor                 dl, cl
            //   8b4df4               | mov                 ecx, dword ptr [ebp - 0xc]
            //   88143e               | mov                 byte ptr [esi + edi], dl
            //   8a4c0105             | mov                 cl, byte ptr [ecx + eax + 5]
            //   02ca                 | add                 cl, dl
            //   8b55f4               | mov                 edx, dword ptr [ebp - 0xc]

        $sequence_14 = { 7305 83c302 eb29 81fb00010000 }
            // n = 4, score = 300
            //   7305                 | jae                 7
            //   83c302               | add                 ebx, 2
            //   eb29                 | jmp                 0x2b
            //   81fb00010000         | cmp                 ebx, 0x100

        $sequence_15 = { e8???????? 68???????? 8d8de4faffff 6804010000 51 0fb7f0 e8???????? }
            // n = 7, score = 300
            //   e8????????           |                     
            //   68????????           |                     
            //   8d8de4faffff         | lea                 ecx, [ebp - 0x51c]
            //   6804010000           | push                0x104
            //   51                   | push                ecx
            //   0fb7f0               | movzx               esi, ax
            //   e8????????           |                     

    condition:
        7 of them and filesize < 1064960
}
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