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 (20201014 | autogenerated rule brought to you by yara-signator)
rule win_coreshell_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-10-14"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.5.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.coreshell"
        malpedia_rule_date = "20201014"
        malpedia_hash = "a7e3bd57eaf12bf3ea29a863c041091ba3af9ac9"
        malpedia_version = "20201014"
        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 ff15???????? 83c40c 3bc6 }
            // n = 4, score = 1000
            //   56                   | push                esi
            //   ff15????????         |                     
            //   83c40c               | add                 esp, 0xc
            //   3bc6                 | cmp                 eax, esi

        $sequence_1 = { 6a01 51 68???????? 52 }
            // n = 4, score = 900
            //   6a01                 | push                1
            //   51                   | push                ecx
            //   68????????           |                     
            //   52                   | push                edx

        $sequence_2 = { 56 6810270000 ff15???????? be06000000 e8???????? 85c0 }
            // n = 6, score = 900
            //   56                   | push                esi
            //   6810270000           | push                0x2710
            //   ff15????????         |                     
            //   be06000000           | mov                 esi, 6
            //   e8????????           |                     
            //   85c0                 | test                eax, eax

        $sequence_3 = { be06000000 e8???????? 85c0 7401 4e 68c0270900 }
            // n = 6, score = 900
            //   be06000000           | mov                 esi, 6
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   7401                 | je                  3
            //   4e                   | dec                 esi
            //   68c0270900           | push                0x927c0

        $sequence_4 = { 68???????? 52 ffd7 ffd0 }
            // n = 4, score = 900
            //   68????????           |                     
            //   52                   | push                edx
            //   ffd7                 | call                edi
            //   ffd0                 | call                eax

        $sequence_5 = { 56 6a00 6a00 681c800000 6a00 }
            // n = 5, score = 800
            //   56                   | push                esi
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   681c800000           | push                0x801c
            //   6a00                 | push                0

        $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 = { 8d041e 50 57 6a08 }
            // n = 4, score = 800
            //   8d041e               | lea                 eax, [esi + ebx]
            //   50                   | push                eax
            //   57                   | push                edi
            //   6a08                 | push                8

        $sequence_8 = { 6a00 6a00 ff15???????? 8bf0 ff15???????? 50 }
            // n = 6, score = 800
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   ff15????????         |                     
            //   8bf0                 | mov                 esi, eax
            //   ff15????????         |                     
            //   50                   | push                eax

        $sequence_9 = { 57 6a08 51 ff15???????? 8bf8 85ff }
            // n = 6, score = 800
            //   57                   | push                edi
            //   6a08                 | push                8
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   8bf8                 | mov                 edi, eax
            //   85ff                 | test                edi, edi

        $sequence_10 = { 50 ff15???????? 83c404 32db }
            // n = 4, score = 800
            //   50                   | push                eax
            //   ff15????????         |                     
            //   83c404               | add                 esp, 4
            //   32db                 | xor                 bl, bl

        $sequence_11 = { c20400 50 a1???????? 6a00 50 }
            // n = 5, score = 800
            //   c20400               | ret                 4
            //   50                   | push                eax
            //   a1????????           |                     
            //   6a00                 | push                0
            //   50                   | push                eax

        $sequence_12 = { 85c0 7402 eb14 c745f000000000 }
            // n = 4, score = 700
            //   85c0                 | test                eax, eax
            //   7402                 | je                  4
            //   eb14                 | jmp                 0x16
            //   c745f000000000       | mov                 dword ptr [ebp - 0x10], 0

        $sequence_13 = { eb14 c745f000000000 68e0930400 ff15???????? }
            // n = 4, score = 700
            //   eb14                 | jmp                 0x16
            //   c745f000000000       | mov                 dword ptr [ebp - 0x10], 0
            //   68e0930400           | push                0x493e0
            //   ff15????????         |                     

        $sequence_14 = { ff15???????? ffd0 85c0 7508 }
            // n = 4, score = 700
            //   ff15????????         |                     
            //   ffd0                 | call                eax
            //   85c0                 | test                eax, eax
            //   7508                 | jne                 0xa

        $sequence_15 = { 50 a3???????? ffd6 a3???????? a1???????? }
            // n = 5, score = 700
            //   50                   | push                eax
            //   a3????????           |                     
            //   ffd6                 | call                esi
            //   a3????????           |                     
            //   a1????????           |                     

        $sequence_16 = { 8bf1 8b4604 85c0 7407 50 ff15???????? 8b36 }
            // n = 7, score = 600
            //   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_17 = { 68???????? 6800080000 8d85fcefffff 50 ff15???????? }
            // n = 5, score = 600
            //   68????????           |                     
            //   6800080000           | push                0x800
            //   8d85fcefffff         | lea                 eax, [ebp - 0x1004]
            //   50                   | push                eax
            //   ff15????????         |                     

        $sequence_18 = { 8d4c2400 56 51 6a00 }
            // n = 4, score = 600
            //   8d4c2400             | lea                 ecx, [esp]
            //   56                   | push                esi
            //   51                   | push                ecx
            //   6a00                 | push                0

        $sequence_19 = { 68???????? 50 ffd6 6a00 6a00 6a00 68???????? }
            // n = 7, score = 600
            //   68????????           |                     
            //   50                   | push                eax
            //   ffd6                 | call                esi
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   68????????           |                     

        $sequence_20 = { ff15???????? 03c0 50 8d95f4fdffff }
            // n = 4, score = 500
            //   ff15????????         |                     
            //   03c0                 | add                 eax, eax
            //   50                   | push                eax
            //   8d95f4fdffff         | lea                 edx, [ebp - 0x20c]

        $sequence_21 = { 52 e8???????? 83c408 33c0 8b4df0 64890d00000000 5f }
            // n = 7, score = 500
            //   52                   | push                edx
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   33c0                 | xor                 eax, eax
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]
            //   64890d00000000       | mov                 dword ptr fs:[0], ecx
            //   5f                   | pop                 edi

        $sequence_22 = { 68???????? 68???????? 8985f0fdffff 8d85f4fdffff 6804010000 50 }
            // n = 6, score = 500
            //   68????????           |                     
            //   68????????           |                     
            //   8985f0fdffff         | mov                 dword ptr [ebp - 0x210], eax
            //   8d85f4fdffff         | lea                 eax, [ebp - 0x20c]
            //   6804010000           | push                0x104
            //   50                   | push                eax

        $sequence_23 = { 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_24 = { ff15???????? eb2f ff15???????? 50 68???????? }
            // n = 5, score = 500
            //   ff15????????         |                     
            //   eb2f                 | jmp                 0x31
            //   ff15????????         |                     
            //   50                   | push                eax
            //   68????????           |                     

        $sequence_25 = { 50 6a00 6a00 53 6a00 6a00 ff15???????? }
            // n = 7, score = 500
            //   50                   | push                eax
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   53                   | push                ebx
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   ff15????????         |                     

        $sequence_26 = { 7312 ff15???????? 0fb6cb 03cf 880431 fec3 ebe6 }
            // n = 7, score = 500
            //   7312                 | jae                 0x14
            //   ff15????????         |                     
            //   0fb6cb               | movzx               ecx, bl
            //   03cf                 | add                 ecx, edi
            //   880431               | mov                 byte ptr [ecx + esi], al
            //   fec3                 | inc                 bl
            //   ebe6                 | jmp                 0xffffffe8

        $sequence_27 = { 53 52 50 68???????? e8???????? 85c0 }
            // n = 6, score = 500
            //   53                   | push                ebx
            //   52                   | push                edx
            //   50                   | push                eax
            //   68????????           |                     
            //   e8????????           |                     
            //   85c0                 | test                eax, eax

        $sequence_28 = { 8b0d???????? 52 50 57 68???????? 51 }
            // n = 6, score = 500
            //   8b0d????????         |                     
            //   52                   | push                edx
            //   50                   | push                eax
            //   57                   | push                edi
            //   68????????           |                     
            //   51                   | push                ecx

        $sequence_29 = { e8???????? 83c404 6804010000 6a08 }
            // n = 4, score = 400
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   6804010000           | push                0x104
            //   6a08                 | push                8

        $sequence_30 = { 52 ff15???????? 0305???????? 50 ff15???????? 83c418 }
            // n = 6, score = 400
            //   52                   | push                edx
            //   ff15????????         |                     
            //   0305????????         |                     
            //   50                   | push                eax
            //   ff15????????         |                     
            //   83c418               | add                 esp, 0x18

        $sequence_31 = { 68???????? 8b0d???????? 51 ff15???????? ffd0 8945fc }
            // n = 6, score = 400
            //   68????????           |                     
            //   8b0d????????         |                     
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   ffd0                 | call                eax
            //   8945fc               | mov                 dword ptr [ebp - 4], eax

        $sequence_32 = { 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_33 = { 8d5508 895d08 8b08 52 }
            // n = 4, score = 300
            //   8d5508               | lea                 edx, [ebp + 8]
            //   895d08               | mov                 dword ptr [ebp + 8], ebx
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   52                   | push                edx

        $sequence_34 = { ffd6 ffd0 68???????? a3???????? }
            // n = 4, score = 300
            //   ffd6                 | call                esi
            //   ffd0                 | call                eax
            //   68????????           |                     
            //   a3????????           |                     

        $sequence_35 = { 50 ff15???????? a1???????? 83c418 }
            // n = 4, score = 300
            //   50                   | push                eax
            //   ff15????????         |                     
            //   a1????????           |                     
            //   83c418               | add                 esp, 0x18

        $sequence_36 = { 68???????? 51 ffd3 ffd0 }
            // n = 4, score = 300
            //   68????????           |                     
            //   51                   | push                ecx
            //   ffd3                 | call                ebx
            //   ffd0                 | call                eax

        $sequence_37 = { 81e2ffff0000 81e2ffff0000 c1ea08 81e2ff000000 }
            // n = 4, score = 300
            //   81e2ffff0000         | and                 edx, 0xffff
            //   81e2ffff0000         | and                 edx, 0xffff
            //   c1ea08               | shr                 edx, 8
            //   81e2ff000000         | and                 edx, 0xff

        $sequence_38 = { 56 51 56 6a01 }
            // n = 4, score = 300
            //   56                   | push                esi
            //   51                   | push                ecx
            //   56                   | push                esi
            //   6a01                 | push                1

        $sequence_39 = { 8be8 8b442410 50 e8???????? }
            // n = 4, score = 300
            //   8be8                 | mov                 ebp, eax
            //   8b442410             | mov                 eax, dword ptr [esp + 0x10]
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_40 = { 8bc2 5e 5f c9 c3 6a08 }
            // n = 6, score = 300
            //   8bc2                 | mov                 eax, edx
            //   5e                   | pop                 esi
            //   5f                   | pop                 edi
            //   c9                   | leave               
            //   c3                   | ret                 
            //   6a08                 | push                8

        $sequence_41 = { 8b55c4 c70200000000 b802000000 8b0d???????? }
            // n = 4, score = 200
            //   8b55c4               | mov                 edx, dword ptr [ebp - 0x3c]
            //   c70200000000         | mov                 dword ptr [edx], 0
            //   b802000000           | mov                 eax, 2
            //   8b0d????????         |                     

        $sequence_42 = { 31db 895588 89da 8b5d88 f7f3 0502000000 }
            // n = 6, score = 200
            //   31db                 | xor                 ebx, ebx
            //   895588               | mov                 dword ptr [ebp - 0x78], edx
            //   89da                 | mov                 edx, ebx
            //   8b5d88               | mov                 ebx, dword ptr [ebp - 0x78]
            //   f7f3                 | div                 ebx
            //   0502000000           | add                 eax, 2

        $sequence_43 = { bf04010000 57 6a08 ff35???????? }
            // n = 4, score = 200
            //   bf04010000           | mov                 edi, 0x104
            //   57                   | push                edi
            //   6a08                 | push                8
            //   ff35????????         |                     

        $sequence_44 = { 56 57 8b3d???????? 68???????? ffd7 8b35???????? 68???????? }
            // n = 7, score = 200
            //   56                   | push                esi
            //   57                   | push                edi
            //   8b3d????????         |                     
            //   68????????           |                     
            //   ffd7                 | call                edi
            //   8b35????????         |                     
            //   68????????           |                     

        $sequence_45 = { f7f1 89d0 8b8dd0feffff 31c8 }
            // n = 4, score = 200
            //   f7f1                 | div                 ecx
            //   89d0                 | mov                 eax, edx
            //   8b8dd0feffff         | mov                 ecx, dword ptr [ebp - 0x130]
            //   31c8                 | xor                 eax, ecx

        $sequence_46 = { c1fa08 894de0 89d1 8b55e0 d3fa 89d6 }
            // n = 6, score = 200
            //   c1fa08               | sar                 edx, 8
            //   894de0               | mov                 dword ptr [ebp - 0x20], ecx
            //   89d1                 | mov                 ecx, edx
            //   8b55e0               | mov                 edx, dword ptr [ebp - 0x20]
            //   d3fa                 | sar                 edx, cl
            //   89d6                 | mov                 esi, edx

        $sequence_47 = { 8908 c74004???????? e8???????? 8b4dcc }
            // n = 4, score = 200
            //   8908                 | mov                 dword ptr [eax], ecx
            //   c74004????????       |                     
            //   e8????????           |                     
            //   8b4dcc               | mov                 ecx, dword ptr [ebp - 0x34]

        $sequence_48 = { 89d0 99 f7f9 8985ecfeffff 31d2 f7f1 31d2 }
            // n = 7, score = 200
            //   89d0                 | mov                 eax, edx
            //   99                   | cdq                 
            //   f7f9                 | idiv                ecx
            //   8985ecfeffff         | mov                 dword ptr [ebp - 0x114], eax
            //   31d2                 | xor                 edx, edx
            //   f7f1                 | div                 ecx
            //   31d2                 | xor                 edx, edx

        $sequence_49 = { ff35???????? ffd6 ffd0 53 }
            // n = 4, score = 200
            //   ff35????????         |                     
            //   ffd6                 | call                esi
            //   ffd0                 | call                eax
            //   53                   | push                ebx

        $sequence_50 = { 39c8 0f84a1020000 8b45c8 8b08 }
            // n = 4, score = 200
            //   39c8                 | cmp                 eax, ecx
            //   0f84a1020000         | je                  0x2a7
            //   8b45c8               | mov                 eax, dword ptr [ebp - 0x38]
            //   8b08                 | mov                 ecx, dword ptr [eax]

        $sequence_51 = { 0f846d030000 e9???????? 8b45dc 8b00 8d65f4 }
            // n = 5, score = 200
            //   0f846d030000         | je                  0x373
            //   e9????????           |                     
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   8d65f4               | lea                 esp, [ebp - 0xc]

    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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