SYMBOLCOMMON_NAMEaka. SYNONYMS
win.coreshell (Back to overview)

Coreshell

aka: SOURFACE

Actor(s): Sofacy


There is no description at this point.

References
2017-02-20Contagio DumpMila Parkour
@online{parkour:20170220:part:c54b5de, author = {Mila Parkour}, title = {{Part I. Russian APT - APT28 collection of samples including OSX XAgent}}, date = {2017-02-20}, organization = {Contagio Dump}, url = {https://contagiodump.blogspot.de/2017/02/russian-apt-apt28-collection-of-samples.html}, language = {English}, urldate = {2019-11-26} } Part I. Russian APT - APT28 collection of samples including OSX XAgent
X-Agent Komplex Coreshell Downdelph HideDRV SEADADDY Sedreco Seduploader X-Agent XTunnel
2015-12-04Kaspersky LabsGReAT
@online{great:20151204:sofacy:b437b35, author = {GReAT}, title = {{Sofacy APT hits high profile targets with updated toolset}}, date = {2015-12-04}, organization = {Kaspersky Labs}, url = {https://securelist.com/sofacy-apt-hits-high-profile-targets-with-updated-toolset/72924/}, language = {English}, urldate = {2020-08-30} } Sofacy APT hits high profile targets with updated toolset
Coreshell Sedreco Seduploader X-Agent Sofacy
2014-08-11Prevenity
@online{prevenity:20140811:mht:d828ead, author = {Prevenity}, title = {{mht, MS12-27 and * malware * .info}}, date = {2014-08-11}, url = {http://malware.prevenity.com/2014/08/malware-info.html}, language = {Polish}, urldate = {2019-11-28} } mht, MS12-27 and * malware * .info
Coreshell
2014FireEyeFireEye
@techreport{fireeye:2014:apt28:27799d1, author = {FireEye}, title = {{APT28}}, date = {2014}, institution = {FireEye}, url = {http://www2.fireeye.com/rs/fireye/images/rpt-apt28.pdf}, language = {English}, urldate = {2020-01-08} } APT28
Coreshell Sedreco X-Agent
2012-12-15Malware Reversing BlogR136a1
@online{r136a1:20121215:disclosure:c36a5a8, author = {R136a1}, title = {{Disclosure of another 0day malware - Initial Dropper and Downloader (Part 1)}}, date = {2012-12-15}, organization = {Malware Reversing Blog}, url = {http://www.malware-reversing.com/2012/12/3-disclosure-of-another-0day-malware.html}, language = {English}, urldate = {2020-01-06} } Disclosure of another 0day malware - Initial Dropper and Downloader (Part 1)
Coreshell
Yara Rules
[TLP:WHITE] win_coreshell_auto (20210616 | Detects win.coreshell.)
rule win_coreshell_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        version = "1"
        description = "Detects win.coreshell."
        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.coreshell"
        malpedia_rule_date = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 56 6810270000 ff15???????? be06000000 e8???????? 85c0 }
            // n = 6, score = 1000
            //   56                   | push                esi
            //   6810270000           | push                0x2710
            //   ff15????????         |                     
            //   be06000000           | mov                 esi, 6
            //   e8????????           |                     
            //   85c0                 | test                eax, eax

        $sequence_1 = { be06000000 e8???????? 85c0 7401 4e 68c0270900 ff15???????? }
            // n = 7, score = 1000
            //   be06000000           | mov                 esi, 6
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   7401                 | je                  3
            //   4e                   | dec                 esi
            //   68c0270900           | push                0x927c0
            //   ff15????????         |                     

        $sequence_2 = { 68???????? 52 ffd7 ffd0 }
            // n = 4, score = 1000
            //   68????????           |                     
            //   52                   | push                edx
            //   ffd7                 | call                edi
            //   ffd0                 | call                eax

        $sequence_3 = { 56 ff15???????? 83c40c 3bc6 }
            // n = 4, score = 1000
            //   56                   | push                esi
            //   ff15????????         |                     
            //   83c40c               | add                 esp, 0xc
            //   3bc6                 | cmp                 eax, esi

        $sequence_4 = { c20400 50 a1???????? 6a00 }
            // n = 4, score = 800
            //   c20400               | ret                 4
            //   50                   | push                eax
            //   a1????????           |                     
            //   6a00                 | push                0

        $sequence_5 = { 50 57 6a08 51 ff15???????? 8bf8 }
            // n = 6, score = 800
            //   50                   | push                eax
            //   57                   | push                edi
            //   6a08                 | push                8
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   8bf8                 | mov                 edi, eax

        $sequence_6 = { 6804010000 6a08 8b15???????? 52 ff15???????? a3???????? }
            // n = 6, score = 800
            //   6804010000           | push                0x104
            //   6a08                 | push                8
            //   8b15????????         |                     
            //   52                   | push                edx
            //   ff15????????         |                     
            //   a3????????           |                     

        $sequence_7 = { 8b15???????? 6a01 51 68???????? }
            // n = 4, score = 800
            //   8b15????????         |                     
            //   6a01                 | push                1
            //   51                   | push                ecx
            //   68????????           |                     

        $sequence_8 = { 51 ff15???????? 8bf8 85ff 750a 5f 5e }
            // n = 7, score = 800
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   8bf8                 | mov                 edi, eax
            //   85ff                 | test                edi, edi
            //   750a                 | jne                 0xc
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_9 = { ff15???????? ffd0 85c0 7508 }
            // n = 4, score = 700
            //   ff15????????         |                     
            //   ffd0                 | call                eax
            //   85c0                 | test                eax, eax
            //   7508                 | jne                 0xa

        $sequence_10 = { 8bf1 8b4604 85c0 7407 50 ff15???????? 8b36 }
            // n = 7, score = 700
            //   8bf1                 | mov                 esi, ecx
            //   8b4604               | mov                 eax, dword ptr [esi + 4]
            //   85c0                 | test                eax, eax
            //   7407                 | je                  9
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b36                 | mov                 esi, dword ptr [esi]

        $sequence_11 = { 68???????? 50 a3???????? ffd6 a3???????? a1???????? 68???????? }
            // n = 7, score = 700
            //   68????????           |                     
            //   50                   | push                eax
            //   a3????????           |                     
            //   ffd6                 | call                esi
            //   a3????????           |                     
            //   a1????????           |                     
            //   68????????           |                     

        $sequence_12 = { 8d4c2400 56 51 6a00 }
            // n = 4, score = 700
            //   8d4c2400             | lea                 ecx, dword ptr [esp]
            //   56                   | push                esi
            //   51                   | push                ecx
            //   6a00                 | push                0

        $sequence_13 = { e8???????? 85c0 7402 eb14 c745f000000000 68e0930400 }
            // n = 6, score = 700
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   7402                 | je                  4
            //   eb14                 | jmp                 0x16
            //   c745f000000000       | mov                 dword ptr [ebp - 0x10], 0
            //   68e0930400           | push                0x493e0

        $sequence_14 = { 51 8b0d???????? 52 50 57 }
            // n = 5, score = 600
            //   51                   | push                ecx
            //   8b0d????????         |                     
            //   52                   | push                edx
            //   50                   | push                eax
            //   57                   | push                edi

        $sequence_15 = { ff15???????? 85c0 894604 740a b801000000 5e 59 }
            // n = 7, score = 600
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   894604               | mov                 dword ptr [esi + 4], eax
            //   740a                 | je                  0xc
            //   b801000000           | mov                 eax, 1
            //   5e                   | pop                 esi
            //   59                   | pop                 ecx

        $sequence_16 = { 68???????? 50 ffd6 6a00 6a00 6a00 }
            // n = 6, score = 600
            //   68????????           |                     
            //   50                   | push                eax
            //   ffd6                 | call                esi
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a00                 | push                0

        $sequence_17 = { 68???????? 6800080000 8d85fcefffff 50 }
            // n = 4, score = 600
            //   68????????           |                     
            //   6800080000           | push                0x800
            //   8d85fcefffff         | lea                 eax, dword ptr [ebp - 0x1004]
            //   50                   | push                eax

        $sequence_18 = { 7312 ff15???????? 0fb6cb 03cf 880431 }
            // n = 5, score = 500
            //   7312                 | jae                 0x14
            //   ff15????????         |                     
            //   0fb6cb               | movzx               ecx, bl
            //   03cf                 | add                 ecx, edi
            //   880431               | mov                 byte ptr [ecx + esi], al

        $sequence_19 = { c745f4469e7f55 c745f8d8a47604 c745ecde489f35 c745f033f5764c }
            // n = 4, score = 500
            //   c745f4469e7f55       | mov                 dword ptr [ebp - 0xc], 0x557f9e46
            //   c745f8d8a47604       | mov                 dword ptr [ebp - 8], 0x476a4d8
            //   c745ecde489f35       | mov                 dword ptr [ebp - 0x14], 0x359f48de
            //   c745f033f5764c       | mov                 dword ptr [ebp - 0x10], 0x4c76f533

        $sequence_20 = { 6aff 8d55f0 52 e8???????? 83c408 33c0 8b4df0 }
            // n = 7, score = 500
            //   6aff                 | push                -1
            //   8d55f0               | lea                 edx, dword ptr [ebp - 0x10]
            //   52                   | push                edx
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   33c0                 | xor                 eax, eax
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]

        $sequence_21 = { 8d85fcefffff 6800080000 50 ff15???????? 83c414 }
            // n = 5, score = 500
            //   8d85fcefffff         | lea                 eax, dword ptr [ebp - 0x1004]
            //   6800080000           | push                0x800
            //   50                   | push                eax
            //   ff15????????         |                     
            //   83c414               | add                 esp, 0x14

        $sequence_22 = { 81e1ffff0000 81e1ffff0000 81e1ff000000 81e1ff000000 }
            // n = 4, score = 500
            //   81e1ffff0000         | and                 ecx, 0xffff
            //   81e1ffff0000         | and                 ecx, 0xffff
            //   81e1ff000000         | and                 ecx, 0xff
            //   81e1ff000000         | and                 ecx, 0xff

        $sequence_23 = { 03cf 880431 fec3 ebe6 }
            // n = 4, score = 500
            //   03cf                 | add                 ecx, edi
            //   880431               | mov                 byte ptr [ecx + esi], al
            //   fec3                 | inc                 bl
            //   ebe6                 | jmp                 0xffffffe8

        $sequence_24 = { ff15???????? 50 68???????? 68???????? 8985f0fdffff }
            // n = 5, score = 500
            //   ff15????????         |                     
            //   50                   | push                eax
            //   68????????           |                     
            //   68????????           |                     
            //   8985f0fdffff         | mov                 dword ptr [ebp - 0x210], eax

        $sequence_25 = { 8bce e8???????? 8bce 8bf8 e8???????? 56 }
            // n = 6, score = 500
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   8bce                 | mov                 ecx, esi
            //   8bf8                 | mov                 edi, eax
            //   e8????????           |                     
            //   56                   | push                esi

        $sequence_26 = { 52 a1???????? 50 68???????? 8b0d???????? 51 ff15???????? }
            // n = 7, score = 400
            //   52                   | push                edx
            //   a1????????           |                     
            //   50                   | push                eax
            //   68????????           |                     
            //   8b0d????????         |                     
            //   51                   | push                ecx
            //   ff15????????         |                     

        $sequence_27 = { 6888130000 ff15???????? c745f000000000 c745f400000000 }
            // n = 4, score = 400
            //   6888130000           | push                0x1388
            //   ff15????????         |                     
            //   c745f000000000       | mov                 dword ptr [ebp - 0x10], 0
            //   c745f400000000       | mov                 dword ptr [ebp - 0xc], 0

        $sequence_28 = { 8d8dfcefffff 51 ff15???????? ba00080000 2bd0 }
            // n = 5, score = 400
            //   8d8dfcefffff         | lea                 ecx, dword ptr [ebp - 0x1004]
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   ba00080000           | mov                 edx, 0x800
            //   2bd0                 | sub                 edx, eax

        $sequence_29 = { e8???????? 8be8 8b442410 50 e8???????? }
            // n = 5, score = 400
            //   e8????????           |                     
            //   8be8                 | mov                 ebp, eax
            //   8b442410             | mov                 eax, dword ptr [esp + 0x10]
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_30 = { 81e2ffff0000 81e2ffff0000 c1ea08 81e2ff000000 }
            // n = 4, score = 400
            //   81e2ffff0000         | and                 edx, 0xffff
            //   81e2ffff0000         | and                 edx, 0xffff
            //   c1ea08               | shr                 edx, 8
            //   81e2ff000000         | and                 edx, 0xff

        $sequence_31 = { 56 51 56 6a01 }
            // n = 4, score = 400
            //   56                   | push                esi
            //   51                   | push                ecx
            //   56                   | push                esi
            //   6a01                 | push                1

        $sequence_32 = { 52 8d85fcefffff 50 ff15???????? 8d8c45fcefffff }
            // n = 5, score = 400
            //   52                   | push                edx
            //   8d85fcefffff         | lea                 eax, dword ptr [ebp - 0x1004]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8d8c45fcefffff       | lea                 ecx, dword ptr [ebp + eax*2 - 0x1004]

        $sequence_33 = { 51 8d95f4edffff 52 68???????? }
            // n = 4, score = 400
            //   51                   | push                ecx
            //   8d95f4edffff         | lea                 edx, dword ptr [ebp - 0x120c]
            //   52                   | push                edx
            //   68????????           |                     

        $sequence_34 = { ff35???????? ff15???????? 0305???????? 50 ff15???????? a1???????? }
            // n = 6, score = 300
            //   ff35????????         |                     
            //   ff15????????         |                     
            //   0305????????         |                     
            //   50                   | push                eax
            //   ff15????????         |                     
            //   a1????????           |                     

        $sequence_35 = { ebec 8bc2 5e 5f c9 c3 6a08 }
            // n = 7, score = 300
            //   ebec                 | jmp                 0xffffffee
            //   8bc2                 | mov                 eax, edx
            //   5e                   | pop                 esi
            //   5f                   | pop                 edi
            //   c9                   | leave               
            //   c3                   | ret                 
            //   6a08                 | push                8

        $sequence_36 = { ffd6 ffd0 68???????? a3???????? }
            // n = 4, score = 300
            //   ffd6                 | call                esi
            //   ffd0                 | call                eax
            //   68????????           |                     
            //   a3????????           |                     

        $sequence_37 = { a1???????? 2506000000 3506000000 99 }
            // n = 4, score = 200
            //   a1????????           |                     
            //   2506000000           | and                 eax, 6
            //   3506000000           | xor                 eax, 6
            //   99                   | cdq                 

        $sequence_38 = { 8b5dd8 8b0b 0fb60c39 0fafd1 c1ea07 8b0e 81c101000000 }
            // n = 7, score = 200
            //   8b5dd8               | mov                 ebx, dword ptr [ebp - 0x28]
            //   8b0b                 | mov                 ecx, dword ptr [ebx]
            //   0fb60c39             | movzx               ecx, byte ptr [ecx + edi]
            //   0fafd1               | imul                edx, ecx
            //   c1ea07               | shr                 edx, 7
            //   8b0e                 | mov                 ecx, dword ptr [esi]
            //   81c101000000         | add                 ecx, 1

        $sequence_39 = { 8b5de8 8918 8b8518ffffff 2b05???????? }
            // n = 4, score = 200
            //   8b5de8               | mov                 ebx, dword ptr [ebp - 0x18]
            //   8918                 | mov                 dword ptr [eax], ebx
            //   8b8518ffffff         | mov                 eax, dword ptr [ebp - 0xe8]
            //   2b05????????         |                     

        $sequence_40 = { 68???????? 53 a3???????? ffd6 a3???????? 68???????? }
            // n = 6, score = 200
            //   68????????           |                     
            //   53                   | push                ebx
            //   a3????????           |                     
            //   ffd6                 | call                esi
            //   a3????????           |                     
            //   68????????           |                     

        $sequence_41 = { 8b3d???????? 68???????? ffd7 8b35???????? 68???????? 50 a3???????? }
            // n = 7, score = 200
            //   8b3d????????         |                     
            //   68????????           |                     
            //   ffd7                 | call                edi
            //   8b35????????         |                     
            //   68????????           |                     
            //   50                   | push                eax
            //   a3????????           |                     

        $sequence_42 = { a1???????? 0503000000 69c803000000 898d78feffff }
            // n = 4, score = 200
            //   a1????????           |                     
            //   0503000000           | add                 eax, 3
            //   69c803000000         | imul                ecx, eax, 3
            //   898d78feffff         | mov                 dword ptr [ebp - 0x188], ecx

        $sequence_43 = { 8b5de8 8918 8b856cffffff 99 }
            // n = 4, score = 200
            //   8b5de8               | mov                 ebx, dword ptr [ebp - 0x18]
            //   8918                 | mov                 dword ptr [eax], ebx
            //   8b856cffffff         | mov                 eax, dword ptr [ebp - 0x94]
            //   99                   | cdq                 

        $sequence_44 = { 53 a3???????? ffd6 68???????? a3???????? ffd7 }
            // n = 6, score = 200
            //   53                   | push                ebx
            //   a3????????           |                     
            //   ffd6                 | call                esi
            //   68????????           |                     
            //   a3????????           |                     
            //   ffd7                 | call                edi

        $sequence_45 = { 8b5dd8 8b0b 0fb60c39 8b3d???????? 8b35???????? 0fafff }
            // n = 6, score = 200
            //   8b5dd8               | mov                 ebx, dword ptr [ebp - 0x28]
            //   8b0b                 | mov                 ecx, dword ptr [ebx]
            //   0fb60c39             | movzx               ecx, byte ptr [ecx + edi]
            //   8b3d????????         |                     
            //   8b35????????         |                     
            //   0fafff               | imul                edi, edi

        $sequence_46 = { 894214 c7421000000000 c7420c00000000 c74208???????? c7420400000000 }
            // n = 5, score = 200
            //   894214               | mov                 dword ptr [edx + 0x14], eax
            //   c7421000000000       | mov                 dword ptr [edx + 0x10], 0
            //   c7420c00000000       | mov                 dword ptr [edx + 0xc], 0
            //   c74208????????       |                     
            //   c7420400000000       | mov                 dword ptr [edx + 4], 0

        $sequence_47 = { 89fa 8bbd70ffffff f7f7 0502000000 }
            // n = 4, score = 200
            //   89fa                 | mov                 edx, edi
            //   8bbd70ffffff         | mov                 edi, dword ptr [ebp - 0x90]
            //   f7f7                 | div                 edi
            //   0502000000           | add                 eax, 2

        $sequence_48 = { bf04010000 57 6a08 ff35???????? ff15???????? }
            // n = 5, score = 200
            //   bf04010000           | mov                 edi, 0x104
            //   57                   | push                edi
            //   6a08                 | push                8
            //   ff35????????         |                     
            //   ff15????????         |                     

        $sequence_49 = { 68???????? a3???????? ffd7 8bd8 68???????? 53 }
            // n = 6, score = 200
            //   68????????           |                     
            //   a3????????           |                     
            //   ffd7                 | call                edi
            //   8bd8                 | mov                 ebx, eax
            //   68????????           |                     
            //   53                   | push                ebx

    condition:
        7 of them and filesize < 303100
}
[TLP:WHITE] win_coreshell_w0   (20180301 | Detects Malware from APT28 incident - SOURFACE is a downloader that obtains a second-stage backdoor from a C2 server.)
rule win_coreshell_w0 {
	meta:
		author = "Florian Roth"
		description = "Detects Malware from APT28 incident - SOURFACE is a downloader that obtains a second-stage backdoor from a C2 server."
		reference = "https://www.fireeye.com/blog/threat-research/2014/10/apt28-a-window-into-russias-cyber-espionage-operations.html"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.coreshell"
        malpedia_version = "20180301"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
	strings:
		$s0 = "coreshell.dll" fullword wide /* PEStudio Blacklist: strings */
		$s1 = "Core Shell Runtime Service" fullword wide /* PEStudio Blacklist: strings */
	condition:
		all of them
}
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