SYMBOLCOMMON_NAMEaka. SYNONYMS
win.bistromath (Back to overview)

BISTROMATH

Actor(s): Lazarus Group


There is no description at this point.

References
2020-02-25SentinelOneJim Walter
@online{walter:20200225:dprk:735f095, author = {Jim Walter}, title = {{DPRK Hidden Cobra Update: North Korean Malicious Cyber Activity}}, date = {2020-02-25}, organization = {SentinelOne}, url = {https://labs.sentinelone.com/dprk-hidden-cobra-update-north-korean-malicious-cyber-activity/}, language = {English}, urldate = {2020-02-27} } DPRK Hidden Cobra Update: North Korean Malicious Cyber Activity
ARTFULPIE BISTROMATH BUFFETLINE CHEESETRAY HOPLIGHT HOTCROISSANT SLICKSHOES
2020-02-14US-CERTUS-CERT
@online{uscert:20200214:malware:cdab5b7, author = {US-CERT}, title = {{Malware Analysis Report (AR20-045A): MAR-10265965-1.v1 - North Korean Trojan: BISTROMATH}}, date = {2020-02-14}, organization = {US-CERT}, url = {https://www.us-cert.gov/ncas/analysis-reports/ar20-045a}, language = {English}, urldate = {2020-02-27} } Malware Analysis Report (AR20-045A): MAR-10265965-1.v1 - North Korean Trojan: BISTROMATH
BISTROMATH
Yara Rules
[TLP:WHITE] win_bistromath_auto (20201023 | autogenerated rule brought to you by yara-signator)
rule win_bistromath_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-12-22"
        version = "1"
        description = "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.bistromath"
        malpedia_rule_date = "20201222"
        malpedia_hash = "30354d830a29f0fbd3714d93d94dea941d77a130"
        malpedia_version = "20201023"
        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 = { 8b4de4 8d5004 8945b0 e8???????? 8945f0 85c0 0f84b7040000 }
            // n = 7, score = 400
            //   8b4de4               | mov                 ecx, dword ptr [ebp - 0x1c]
            //   8d5004               | lea                 edx, [eax + 4]
            //   8945b0               | mov                 dword ptr [ebp - 0x50], eax
            //   e8????????           |                     
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   85c0                 | test                eax, eax
            //   0f84b7040000         | je                  0x4bd

        $sequence_1 = { 8bd1 56 57 33f6 8d7a01 660f1f440000 8a02 }
            // n = 7, score = 400
            //   8bd1                 | mov                 edx, ecx
            //   56                   | push                esi
            //   57                   | push                edi
            //   33f6                 | xor                 esi, esi
            //   8d7a01               | lea                 edi, [edx + 1]
            //   660f1f440000         | nop                 word ptr [eax + eax]
            //   8a02                 | mov                 al, byte ptr [edx]

        $sequence_2 = { ff75f0 8b4df8 ba01000000 e8???????? 83c404 ba70000000 8bce }
            // n = 7, score = 400
            //   ff75f0               | push                dword ptr [ebp - 0x10]
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   ba01000000           | mov                 edx, 1
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   ba70000000           | mov                 edx, 0x70
            //   8bce                 | mov                 ecx, esi

        $sequence_3 = { eb03 8b5d14 837c242800 8b44241c 0f85e6010000 85f6 0f84de010000 }
            // n = 7, score = 400
            //   eb03                 | jmp                 5
            //   8b5d14               | mov                 ebx, dword ptr [ebp + 0x14]
            //   837c242800           | cmp                 dword ptr [esp + 0x28], 0
            //   8b44241c             | mov                 eax, dword ptr [esp + 0x1c]
            //   0f85e6010000         | jne                 0x1ec
            //   85f6                 | test                esi, esi
            //   0f84de010000         | je                  0x1e4

        $sequence_4 = { 8d4df8 e8???????? 8bf0 85f6 0f8542feffff 8b7df4 33c0 }
            // n = 7, score = 400
            //   8d4df8               | lea                 ecx, [ebp - 8]
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax
            //   85f6                 | test                esi, esi
            //   0f8542feffff         | jne                 0xfffffe48
            //   8b7df4               | mov                 edi, dword ptr [ebp - 0xc]
            //   33c0                 | xor                 eax, eax

        $sequence_5 = { ffd0 8b5d08 83c408 8bf0 eb3c 8b483c 3931 }
            // n = 7, score = 400
            //   ffd0                 | call                eax
            //   8b5d08               | mov                 ebx, dword ptr [ebp + 8]
            //   83c408               | add                 esp, 8
            //   8bf0                 | mov                 esi, eax
            //   eb3c                 | jmp                 0x3e
            //   8b483c               | mov                 ecx, dword ptr [eax + 0x3c]
            //   3931                 | cmp                 dword ptr [ecx], esi

        $sequence_6 = { c1e108 0bc8 49 0fb7c1 0fb64a03 66c1e108 8945e4 }
            // n = 7, score = 400
            //   c1e108               | shl                 ecx, 8
            //   0bc8                 | or                  ecx, eax
            //   49                   | dec                 ecx
            //   0fb7c1               | movzx               eax, cx
            //   0fb64a03             | movzx               ecx, byte ptr [edx + 3]
            //   66c1e108             | shl                 cx, 8
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax

        $sequence_7 = { e8???????? 8d8560ffffff c745fc0d000000 50 8d85c0feffff 83cb10 50 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   8d8560ffffff         | lea                 eax, [ebp - 0xa0]
            //   c745fc0d000000       | mov                 dword ptr [ebp - 4], 0xd
            //   50                   | push                eax
            //   8d85c0feffff         | lea                 eax, [ebp - 0x140]
            //   83cb10               | or                  ebx, 0x10
            //   50                   | push                eax

        $sequence_8 = { c1e818 53 88411c 8bc2 c1e810 88411d 8bc2 }
            // n = 7, score = 400
            //   c1e818               | shr                 eax, 0x18
            //   53                   | push                ebx
            //   88411c               | mov                 byte ptr [ecx + 0x1c], al
            //   8bc2                 | mov                 eax, edx
            //   c1e810               | shr                 eax, 0x10
            //   88411d               | mov                 byte ptr [ecx + 0x1d], al
            //   8bc2                 | mov                 eax, edx

        $sequence_9 = { ff75fc ff15???????? 8bf8 85f6 7407 56 ff15???????? }
            // n = 7, score = 400
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   ff15????????         |                     
            //   8bf8                 | mov                 edi, eax
            //   85f6                 | test                esi, esi
            //   7407                 | je                  9
            //   56                   | push                esi
            //   ff15????????         |                     

    condition:
        7 of them and filesize < 33816576
}
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