SYMBOLCOMMON_NAMEaka. SYNONYMS
win.cmstar (Back to overview)

CMSTAR

aka: meciv

There is no description at this point.

References
2018-02-13Twitter (@ClearskySec)ClearSky
@online{clearsky:20180213:enfal:e063cf1, author = {ClearSky}, title = {{Tweet on Enfal loader}}, date = {2018-02-13}, organization = {Twitter (@ClearskySec)}, url = {https://twitter.com/ClearskySec/status/963829930776723461}, language = {English}, urldate = {2019-07-10} } Tweet on Enfal loader
CMSTAR
2017-09-28Palo Alto Networks Unit 42Josh Grunzweig, Robert Falcone
@online{grunzweig:20170928:threat:835bf8e, author = {Josh Grunzweig and Robert Falcone}, title = {{Threat Actors Target Government of Belarus Using CMSTAR Trojan}}, date = {2017-09-28}, organization = {Palo Alto Networks Unit 42}, url = {https://researchcenter.paloaltonetworks.com/2017/09/unit42-threat-actors-target-government-belarus-using-cmstar-trojan}, language = {English}, urldate = {2019-12-20} } Threat Actors Target Government of Belarus Using CMSTAR Trojan
BYEBY CMSTAR
2017-09-28Palo Alto Networks Unit 42Josh Grunzweig, Robert Falcone
@online{grunzweig:20170928:threat:8a5db81, author = {Josh Grunzweig and Robert Falcone}, title = {{Threat Actors Target Government of Belarus Using CMSTAR Trojan}}, date = {2017-09-28}, organization = {Palo Alto Networks Unit 42}, url = {https://unit42.paloaltonetworks.com/unit42-threat-actors-target-government-belarus-using-cmstar-trojan}, language = {English}, urldate = {2022-07-25} } Threat Actors Target Government of Belarus Using CMSTAR Trojan
BYEBY CMSTAR Vicious Panda
2016-03-14Palo Alto Networks Unit 42Josh Grunzweig, Robert Falcone, Bryan Lee
@online{grunzweig:20160314:digital:b6ddc60, author = {Josh Grunzweig and Robert Falcone and Bryan Lee}, title = {{Digital Quartermaster Scenario Demonstrated in Attacks Against the Mongolian Government}}, date = {2016-03-14}, organization = {Palo Alto Networks Unit 42}, url = {https://researchcenter.paloaltonetworks.com/2016/03/digital-quartermaster-scenario-demonstrated-in-attacks-against-the-mongolian-government/}, language = {English}, urldate = {2019-12-20} } Digital Quartermaster Scenario Demonstrated in Attacks Against the Mongolian Government
BBSRAT CMSTAR
Yara Rules
[TLP:WHITE] win_cmstar_auto (20221125 | Detects win.cmstar.)
rule win_cmstar_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-11-21"
        version = "1"
        description = "Detects win.cmstar."
        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.cmstar"
        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 = { 53 56 bb04010000 57 53 }
            // n = 5, score = 800
            //   53                   | push                ebx
            //   56                   | push                esi
            //   bb04010000           | mov                 ebx, 0x104
            //   57                   | push                edi
            //   53                   | push                ebx

        $sequence_1 = { ff15???????? 8bc6 e9???????? 6a10 8d45d0 53 }
            // n = 6, score = 800
            //   ff15????????         |                     
            //   8bc6                 | mov                 eax, esi
            //   e9????????           |                     
            //   6a10                 | push                0x10
            //   8d45d0               | lea                 eax, [ebp - 0x30]
            //   53                   | push                ebx

        $sequence_2 = { 8b45d8 836dfc10 ff75fc 8945e0 8b45dc 83c310 8945e4 }
            // n = 7, score = 800
            //   8b45d8               | mov                 eax, dword ptr [ebp - 0x28]
            //   836dfc10             | sub                 dword ptr [ebp - 4], 0x10
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   8945e0               | mov                 dword ptr [ebp - 0x20], eax
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   83c310               | add                 ebx, 0x10
            //   8945e4               | mov                 dword ptr [ebp - 0x1c], eax

        $sequence_3 = { 7504 6a03 eb0d 803b4d }
            // n = 4, score = 800
            //   7504                 | jne                 6
            //   6a03                 | push                3
            //   eb0d                 | jmp                 0xf
            //   803b4d               | cmp                 byte ptr [ebx], 0x4d

        $sequence_4 = { ff15???????? 6a04 e8???????? be00040000 }
            // n = 4, score = 800
            //   ff15????????         |                     
            //   6a04                 | push                4
            //   e8????????           |                     
            //   be00040000           | mov                 esi, 0x400

        $sequence_5 = { ff15???????? 6a03 58 5f 5e 5b c9 }
            // n = 7, score = 800
            //   ff15????????         |                     
            //   6a03                 | push                3
            //   58                   | pop                 eax
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx
            //   c9                   | leave               

        $sequence_6 = { 8b4dec c1e802 6a04 52 8d0481 }
            // n = 5, score = 800
            //   8b4dec               | mov                 ecx, dword ptr [ebp - 0x14]
            //   c1e802               | shr                 eax, 2
            //   6a04                 | push                4
            //   52                   | push                edx
            //   8d0481               | lea                 eax, [ecx + eax*4]

        $sequence_7 = { 8945e8 ff75e4 8b45e8 ff75e0 ff30 e8???????? 8b4df8 }
            // n = 7, score = 800
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   ff75e4               | push                dword ptr [ebp - 0x1c]
            //   8b45e8               | mov                 eax, dword ptr [ebp - 0x18]
            //   ff75e0               | push                dword ptr [ebp - 0x20]
            //   ff30                 | push                dword ptr [eax]
            //   e8????????           |                     
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]

        $sequence_8 = { 8b54241c 881c2f 47 3bfa 7290 5d }
            // n = 6, score = 100
            //   8b54241c             | mov                 edx, dword ptr [esp + 0x1c]
            //   881c2f               | mov                 byte ptr [edi + ebp], bl
            //   47                   | inc                 edi
            //   3bfa                 | cmp                 edi, edx
            //   7290                 | jb                  0xffffff92
            //   5d                   | pop                 ebp

        $sequence_9 = { 83ec10 8bcc 89642420 8811 }
            // n = 4, score = 100
            //   83ec10               | sub                 esp, 0x10
            //   8bcc                 | mov                 ecx, esp
            //   89642420             | mov                 dword ptr [esp + 0x20], esp
            //   8811                 | mov                 byte ptr [ecx], dl

        $sequence_10 = { f2ae f7d1 49 8dbc2418040000 }
            // n = 4, score = 100
            //   f2ae                 | repne scasb         al, byte ptr es:[edi]
            //   f7d1                 | not                 ecx
            //   49                   | dec                 ecx
            //   8dbc2418040000       | lea                 edi, [esp + 0x418]

        $sequence_11 = { 8a441420 bf???????? 8882a0430010 83c9ff 33c0 42 f2ae }
            // n = 7, score = 100
            //   8a441420             | mov                 al, byte ptr [esp + edx + 0x20]
            //   bf????????           |                     
            //   8882a0430010         | mov                 byte ptr [edx + 0x100043a0], al
            //   83c9ff               | or                  ecx, 0xffffffff
            //   33c0                 | xor                 eax, eax
            //   42                   | inc                 edx
            //   f2ae                 | repne scasb         al, byte ptr es:[edi]

        $sequence_12 = { 8bd5 8a06 2a01 7902 045e }
            // n = 5, score = 100
            //   8bd5                 | mov                 edx, ebp
            //   8a06                 | mov                 al, byte ptr [esi]
            //   2a01                 | sub                 al, byte ptr [ecx]
            //   7902                 | jns                 4
            //   045e                 | add                 al, 0x5e

        $sequence_13 = { 4a 81ca00ffffff 42 8a1402 8a1c2f 32da }
            // n = 6, score = 100
            //   4a                   | dec                 edx
            //   81ca00ffffff         | or                  edx, 0xffffff00
            //   42                   | inc                 edx
            //   8a1402               | mov                 dl, byte ptr [edx + eax]
            //   8a1c2f               | mov                 bl, byte ptr [edi + ebp]
            //   32da                 | xor                 bl, dl

        $sequence_14 = { 741e 8a441420 bf???????? 8882a8430010 }
            // n = 4, score = 100
            //   741e                 | je                  0x20
            //   8a441420             | mov                 al, byte ptr [esp + edx + 0x20]
            //   bf????????           |                     
            //   8882a8430010         | mov                 byte ptr [edx + 0x100043a8], al

        $sequence_15 = { 83c408 84c0 0f8563050000 8d8c24dc120000 68???????? }
            // n = 5, score = 100
            //   83c408               | add                 esp, 8
            //   84c0                 | test                al, al
            //   0f8563050000         | jne                 0x569
            //   8d8c24dc120000       | lea                 ecx, [esp + 0x12dc]
            //   68????????           |                     

    condition:
        7 of them and filesize < 4268032
}
[TLP:WHITE] win_cmstar_w0   (20170413 | Detects CMStar Malware)
import "pe"

rule win_cmstar_w0 {
    meta:
        description = "Detects CMStar Malware"
        author = "Florian Roth"
        reference = "https://goo.gl/pTffPA"
        date = "2017-10-03"
        hash = "16697c95db5add6c1c23b2591b9d8eec5ed96074d057b9411f0b57a54af298d5"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.cmstar"
        malpedia_version = "20170413"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:
        $s1 = "UpdateService.tmp" fullword ascii
        $s2 = "StateNum:%d,FileSize:%d" fullword ascii
    condition:
        uint16(0) == 0x5a4d and filesize < 100KB and (pe.imphash() == "22021985de78a48ea8fb82a2ff9eb693" or pe.exports("WinCred") or all of them)
}
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