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 (20230125 | Detects win.nachocheese.)
rule win_nachocheese_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        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 = "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 = { 48 ba???????? 2bd0 83c2fe 8d4813 }
            // n = 5, score = 300
            //   48                   | dec                 eax
            //   ba????????           |                     
            //   2bd0                 | sub                 edx, eax
            //   83c2fe               | add                 edx, -2
            //   8d4813               | lea                 ecx, [eax + 0x13]

        $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 = { 0fb713 668b4df0 6a06 6a01 52 }
            // n = 5, score = 300
            //   0fb713               | movzx               edx, word ptr [ebx]
            //   668b4df0             | mov                 cx, word ptr [ebp - 0x10]
            //   6a06                 | push                6
            //   6a01                 | push                1
            //   52                   | push                edx

        $sequence_4 = { 32d1 88143e 8a4805 02ca }
            // n = 4, score = 300
            //   32d1                 | xor                 dl, cl
            //   88143e               | mov                 byte ptr [esi + edi], dl
            //   8a4805               | mov                 cl, byte ptr [eax + 5]
            //   02ca                 | add                 cl, dl

        $sequence_5 = { 7305 83c303 eb1c 81fb00000100 }
            // n = 4, score = 300
            //   7305                 | jae                 7
            //   83c303               | add                 ebx, 3
            //   eb1c                 | jmp                 0x1e
            //   81fb00000100         | cmp                 ebx, 0x10000

        $sequence_6 = { 50 e8???????? 83c410 56 e8???????? 83c404 85c0 }
            // n = 7, score = 300
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   56                   | push                esi
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   85c0                 | test                eax, eax

        $sequence_7 = { 0fbec3 83c40c 83f803 0f8781000000 }
            // n = 4, score = 300
            //   0fbec3               | movsx               eax, bl
            //   83c40c               | add                 esp, 0xc
            //   83f803               | cmp                 eax, 3
            //   0f8781000000         | ja                  0x87

        $sequence_8 = { 50 e8???????? 83c410 837dfc00 7504 6a01 }
            // n = 6, score = 300
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   837dfc00             | cmp                 dword ptr [ebp - 4], 0
            //   7504                 | jne                 6
            //   6a01                 | push                1

        $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 = { 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_11 = { 33c0 eb1e a1???????? 8d5604 }
            // n = 4, score = 300
            //   33c0                 | xor                 eax, eax
            //   eb1e                 | jmp                 0x20
            //   a1????????           |                     
            //   8d5604               | lea                 edx, [esi + 4]

        $sequence_12 = { 7305 83c302 eb29 81fb00010000 7305 }
            // n = 5, score = 300
            //   7305                 | jae                 7
            //   83c302               | add                 ebx, 2
            //   eb29                 | jmp                 0x2b
            //   81fb00010000         | cmp                 ebx, 0x100
            //   7305                 | jae                 7

        $sequence_13 = { 0fb7970c010000 52 6a3b 56 e8???????? 50 e8???????? }
            // n = 7, score = 300
            //   0fb7970c010000       | movzx               edx, word ptr [edi + 0x10c]
            //   52                   | push                edx
            //   6a3b                 | push                0x3b
            //   56                   | push                esi
            //   e8????????           |                     
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_14 = { 3d9f000000 7e0d 33c0 c3 }
            // n = 4, score = 300
            //   3d9f000000           | cmp                 eax, 0x9f
            //   7e0d                 | jle                 0xf
            //   33c0                 | xor                 eax, eax
            //   c3                   | ret                 

        $sequence_15 = { 3d9c000000 7c07 3d9f000000 7e0d }
            // n = 4, score = 300
            //   3d9c000000           | cmp                 eax, 0x9c
            //   7c07                 | jl                  9
            //   3d9f000000           | cmp                 eax, 0x9f
            //   7e0d                 | jle                 0xf

    condition:
        7 of them and filesize < 1064960
}
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