Tag Archives: Ransomware

Nokoyawa Ransomware

Published / by jeff / Leave a Comment

In recent months, new ransomware has been discovered called Nokoyawa, which has become a considerable threat for businesses worldwide. Nokoyawa targets Windows operating systems and propagates through the network via remote execution protocols, which enables the ransomware to impact a large number of systems with minimal exposure.

Nokoyawa encrypts files on infected systems and appends filenames with “.nokoyawa” extension. It then creates a ransom note named “HOW_TO_RECOVER_YOUR_FILES.html” in all encrypted directories, with instructions on how to pay the ransom amount to get the decryption key. The ransom note also serves as proof of the successful encryption of files.

Nokoyawa has multiple communication channels with the command and control infrastructure. The malware sends information about the infected system to the remote server, receives instructions from the server, and sends back the necessary logs and user credentials back to the server. In this way, the ransomware makes it almost impossible to track down the attacker’s location.

To identify the presence of Nokoyawa ransomware, we have observed some indicators of compromise (IOCs) in the infected systems. The IOCs are as follows:

  • Network traffic to IP on port 443
  • Network traffic to IP on port 80
  • IOCs in PowerShell command-lines such as Base64-encoded strings, file paths, processes, and registry keys

Organizations can mitigate the risks of Nokoyawa by implementing proper security measures such as data backup and recovery systems, file and folder permission policies, email filters, and antivirus programs. Additionally, keeping systems and software up to date by applying security patches can also help to prevent the spread of Nokoyawa ransomware.

In conclusion, Nokoyawa ransomware is a significant threat to businesses and organizations. Recognizing the IOCs and applying preventive measures can help organizations safeguard against this malicious software. Maintaining updated security standards and being vigilant about suspicious network activity are essential components of a proactive security strategy.


Steps to respond to ransomware

Published / by jeff / Leave a Comment

In the face of increasing ransomware attacks, it has become essential to understand the necessary steps to respond to such threats effectively. If you suspect ransomware on your system, it’s imperative to take prompt action and follow the appropriate response steps to minimize the impact and recover data. Firstly, it’s crucial to disconnect the infected system from the internet to prevent further propagation of the ransomware throughout the network. Next, you must identify the type of ransomware via its extension or ransom note left on the system. It’s important to gather as much information as possible about the ransomware to determine the appropriate response.

If adequate backups of the affected data are available, it’s essential to restore them immediately. Ensure that you verify their integrity and perform a scan for any remaining traces of the ransomware. If backups aren’t available, consult with IT security professionals for possible decryption tools or approaches. However, using decryption tools can be risky and may result in additional system damage, so it should only be attempted under expert guidance.

If ransom payment is considered, it is strongly advised to consult law enforcement and IT security experts before proceeding. Ransom payment may not guarantee the safe recovery of data and can incentivize further ransomware attacks. After recovery, it’s essential to assess and improve system security to prevent future ransomware threats. Regularly updating software, implementing firewalls and antivirus programs, and educating employees on best cybersecurity practices can significantly reduce the risk of ransomware attacks.

To sum it up, responding to ransomware requires a quick response, identifying the ransomware type, restoring backups, consulting IT security professionals for decryption, considering legal and expert advice before making ransom payment, and implementing improved system security measures. Taking these steps can ensure an effective response to ransomware attacks and protect data from future threats.

Boozallen Report on Petya

Published / by jeff / Leave a Comment

I came across this write up by boozallen yesterday, and found it had some very interesting thoughts and insight to how and what happened.




1. Four VirusTotal users uploaded the compiled VBS backdoors along with other malicious files, including the
TeleBots telegram-based backdoor, PowerShell post-exploitation scripts, Mimikatz, and other tools. For each
user, these uploads occurred within the same one- to two-day time period.
2. In most cases, these files were uploaded several months prior to the 27 June Petya incident.
3. Booz Allen Cyber4Sight also determined that in several cases, these submitters also uploaded files
associated with the MEDoc update utility to VirusTotal. This shows that these submitters were also likely
users of the MEDoc software, and the inclusion of these files with the files identified in number 1 (above)
demonstrates that MEDoc-related processes may have facilitated the installation vector for this software.


These past few months have been quite interesting.  The scale and ease of WannaCry and the more recent  Petya/Non Petya attacks, have created a greater awareness for individuals outside of the security world.  Major news outlets are interested in these events as they transpire and this can only be a good thing.  I still believe we are many years away from individuals and business truly changing their mindsets and realise that just reacting to these events is not enough, and more time and effort is spent on how these applications are designed and how we approach security.  We need to try harder to make applications and hardware secure by design and not rely on 3rd party products afterwards to make the product “secure”.

We are going to have several more large scale events like this until the mindset changes, humans are stubborn and we do not like to change – however this is something we must do.



Talos Update on M.E.Doc

Published / by jeff / Leave a Comment



The Nyetya attack was a destructive ransomware variant that affected many organizations inside of Ukraine and multinational corporations with operations in Ukraine. In cooperation with Cisco Advanced Services Incident Response, Talos identified several key aspects of the attack. The investigation found a supply chain-focused attack at M.E.Doc software that delivered a destructive payload disguised as ransomware. By utilizing stolen credentials, the actor was able to manipulate the update server for M.E.Doc to proxy connections to an actor-controlled server. Based on the findings, Talos remains confident that the attack was destructive in nature. The effects were broad reaching, with Ukraine Cyber police confirming over 2000 affected companies in Ukraine alone.
This is another good article and write up by Talos.
Gives a lot more useful insight as to how this happened, another good read, will be interesting to see how this continues to develop over the next few days and weeks.

Backdoor in M.E.Doc Application

Published / by jeff / Leave a Comment

I came across an interesting article today, with regards to the Petya / NotPetya cyber attack from last week.  This is a very good write up and analysis of how the organisation M.E.Doc appears to have been compromised and used to spread the malware in a series of updates for the software it produces.

This demonstrates how devastating these types of compromises can be and as a defender can make it very difficult to identify and stop this type of attack from happening, if you happen to be the target of said attack.

I suggest you read this very good article!



Analysis of TeleBots’ cunning backdoor

On the 27th of June 2017, a new cyberattack hit many computer systems in Ukraine, as well as in other countries. That attack was spearheaded by the malware ESET products detect as Diskcoder.C(aka ExPetr, PetrWrap, Petya, or NotPetya). This malware masquerades as typical ransomware: it encrypts the data on the computer and demands $300 bitcoins for recovery. In fact, the malware authors’ intention was to cause damage, so they did all that they could to make data decryption very unlikely.


Another good write up by bleeping computer that contains more information.



Conspiracy theories

Last week, a blog post from a Ukrainian web developer went viral, after it hinted that the real culprit behind the hacked server could have been M.E.Doc’s web host, Wnet, a company that has been accused of having ties to Russia’s intelligence service (FSB).

An investigation into the man’s accusations revealed that the SBU had raided the web host on June 1, for “illegal traffic routing to Crimea in favor of Russian special services.”


Do not pay to Petra Ransomware Email

Published / by jeff / Leave a Comment

During the afternoon it emerged that the “PetrWrap/Petya” malware is currently spreading quickly in many places, including Ukraine.

Here are the facts that we can contribute to “PetrWrap/Petya”:
– Since midday it is no longer possible for the blackmailers to access the email account or send emails.
– Sending emails to the account is no longer possible either.


It’s never a good idea to pay the ransom, even if they had the intention to give you your decryption code, they are not even going to be receiving  your email.

Patch and Backup.

Petya Ransomware Information

Published / by jeff / Leave a Comment

#petya #petrWrap #notPetya


Ransomware attack.


This gist was built by the community of the researchers and was scribed by Kir and Igor from the QIWI/Vulners.
We are grateful for the help of all those who sent us the data, links and information.
Together we can make this world a better place!

Gist updates

Recent news, blog posts and mentions

Recent news from THN/Threatpost/Blogs

Research list

Helpful vaccine (not killswitch!)

Looks like if you block C:\Windows\perfc.dat from writing/executing - stops #Petya. Is used for rundll32 import.
Local kill switch - create file "C:\Windows\perfc"
It kills WMI vector. Still need to patch MS17-010 for full protection.


Group Policy Preferences to deploy the NotPetya vaccine


SCCM vaccine



Infected with #Petya? DON’T PAY RANSOM, You wouldn’t get your files back. Email used by criminals has been Suspended.


Bitcoin wallet monitoring



Archive password: virus

Thanks to the https://twitter.com/OxFemale for the initial malware body.

Source code:

  • Archive password: virus

Thanks to the @Sn0wFX_:

Initial vector:

Ransomware includes:

  • Modified EternalBlue exploit
  • A vulnerability in a third-party Ukrainian software product
  • A second SMB network exploit

Origin (NO PROOF):

Petya was known to be RaaS (Ransomware-as-a-Service), selling on Tor hidden services. Looks like WannaCry copycat. Attribution will be hard.

AvP Bypass

Confirmed AvP bypasing trick is being used by Petya ransomware to evade 6 popular anti-virus signatures (script)




PSEXEC: %PROGRAMDATA%\dllhost.dat is dropped and is legit PSEXEC bin

Remote WMI, “process call create \"C:\\Windows\\System32\\rundll32.exe \\\"C:\\Windows\\perfc.dat\\\" #1”

Log clean, «wevtutil cl Setup & wevtutil cl System & wevtutil cl Security & wevtutil cl Application & fsutil usn deletejournal /D %c:»

Creates a scheduled task that reboots 1 hour after infection. If task removed before the hour, does not reschedule and can buy time

Petya also attempts to kill Exchange & MySQL if they are running.  If you host either of these services and notice them die, this is including in it's infection process (svchost.exe) // by Mike "Bones" Flowers:

Exec: C:\\windows\\system32\\cmd.exe
Params: /c taskkill.exe /f /im Microsoft.Exchange.*
Exec: C:\\windows\\system32\\cmd.exe
Params: /c taskkill.exe /f /im MSExchange*
Exec: C:\\windows\\system32\\cmd.exe
Params: /c taskkill.exe /f /im sqlserver.exe
Exec: C:\\windows\\system32\\cmd.exe
Params: /c taskkill.exe /f /im sqlwriter.exe
Exec: C:\\windows\\system32\\cmd.exe
Params: /c taskkill.exe /f /im mysqld.exe
The new ransomware can also spread using an exploit for the Server Message Block (SMB) vulnerability CVE-2017-0144 (also known as EternalBlue), which was fixed in security update MS17-010 and was also exploited by WannaCrypt to spread to out-of-date machines. In addition, this ransomware also uses a second exploit for CVE-2017-0145 (also known as EternalRomance, and fixed by the same bulletin)

Machines that are patched against these exploits (with security update MS17-010 https://technet.microsoft.com/en-us/library/security/ms17-010.aspx) or have disabled SMBv1 (https://support.microsoft.com/kb/2696547) are not affected by this particular spreading mechanism

Test local account behavior [NOT TESTED]:

Don’t know if you have also noticed, but it only encrypted the MFT records for my test user account profile folders, the default Windows accounts Administrator, default user etc were all untouched, my test account was local so I don’t know what behaviour would be expected for domain account profile folders.

100% on the sample used by me and on a standalone computer, user files were encrypted prior to reboot and the malware was not able to escalate privileges to deploy the MFT encryption payload, no instructions were deposited about recovering these files


Possible IP addresses:


iva76y3pr@outlook.com         // by WhiteWolfCyber
carmellar4hegp@outlook.com    // by WhiteWolfCyber
amanda44i8sq@outlook.com      // by WhiteWolfCyber

Email forms and attachment:

The subject in this case are formed like that (for targed "targed.emailName@targedDomain.com"):

The body:
Hello targed.emailName,

You will be billed $ 2,273.42 on your Visa card momentarily.
Go through attachment to avoid it.
Password is 6089

With appreciation!

Attached file name:


Targeted extensions by @GasGeverij









Droppers sent via email by WhiteWolfCyber:


Codexgigas team:


SNORT rules for the detection by Positive Technologies (ptsecurity.com):

alert tcp any any -> $HOME_NET 445 (msg: "[PT Open] Unimplemented Trans2 Sub-Command code. Possible ETERNALBLUE (WannaCry, Petya) tool"; flow: to_server, established; content: "|FF|SMB2|00 00 00 00|"; depth: 9; offset: 4; byte_test: 2, >, 0x0008, 52, relative, little; pcre: "/\xFFSMB2\x00\x00\x00\x00.{52}(?:\x04|\x09|\x0A|\x0B|\x0C|\x0E|\x11)\x00/"; flowbits: set, SMB.Trans2.SubCommand.Unimplemented; reference: url, msdn.microsoft.com/en-us/library/ee441654.aspx; classtype: attempted-admin; sid: 10001254; rev: 2;)

alert tcp any any -> $HOME_NET 445 (msg: "[PT Open] ETERNALBLUE (WannaCry, Petya) SMB MS Windows RCE"; flow: to_server, established; content: "|FF|SMB3|00 00 00 00|"; depth: 9; offset: 4; flowbits: isset, SMB.Trans2.SubCommand.Unimplemented.Code0E; threshold: type limit, track by_src, seconds 60, count 1; reference: cve, 2017-0144; classtype: attempted-admin; sid: 10001255; rev: 3;)

alert tcp any any -> $HOME_NET 445 (msg: "[PT Open] Trans2 Sub-Command 0x0E. Likely ETERNALBLUE (WannaCry, Petya) tool"; flow: to_server, established; content: "|FF|SMB2|00 00 00 00|"; depth: 9; offset: 4; content: "|0E 00|"; distance: 52; within: 2; flowbits: set, SMB.Trans2.SubCommand.Unimplemented.Code0E; reference: url, msdn.microsoft.com/en-us/library/ee441654.aspx; classtype: attempted-admin; sid: 10001256; rev: 2;)

alert tcp any any -> $HOME_NET 445 (msg: "[PT Open] Petya ransomware perfc.dat component"; flow: to_server, established, no_stream; content: "|fe 53 4d 42|"; offset: 4; depth: 4; content: "|05 00|"; offset: 16; depth: 2; byte_jump: 2, 112, little, from_beginning, post_offset 4; content: "|70 00 65 00 72 00 66 00 63 00 2e 00 64 00 61 00 74 00|"; distance:0; classtype:suspicious-filename-detect; sid: 10001443; rev: 1;)

alert tcp any any -> $HOME_NET 445 (msg:"[PT Open] SMB2 Create PSEXESVC.EXE"; flow:to_server, established, no_stream; content: "|fe 53 4d 42|"; offset: 4; depth: 4; content: "|05 00|"; offset: 16; depth: 2; byte_jump: 2, 112, little, from_beginning, post_offset 4; content:"|50 00 53 00 45 00 58 00 45 00 53 00 56 00 43 00 2e 00 45 00 58 00 45|"; distance:0; classtype:suspicious-filename-detect; sid: 10001444; rev:1;)

Sagan log analysis rules for the detection by Quadrant Information Security (quadrantsec.com) – Note: These are NOT Snort/Suricata rules! See http://sagan.io for more details:

alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[WINDOWS-MALWARE] Petya payload delivery SHA256 hash detected - Open source"; meta_content: "%sagan%",64b0b58a2c030c77fdb2b537b2fcc4af432bc55ffb36599a31d418c7c69e94b1,027cc450ef5f8c5f653329641ec1fed91f694e0d229928963b30f6b0d7d3a745,027cc450ef5f8c5f653329641ec1fed91f694e0d229928963b30f6b0d7d3a745,64b0b58a2c030c77fdb2b537b2fcc4af432bc55ffb36599a31d418c7c69e94b1,027cc450ef5f8c5f653329641ec1fed91f694e0d229928963b30f6b0d7d3a745,fe2e5d0543b4c8769e401ec216d78a5a3547dfd426fd47e097df04a5f7d6d206,ee29b9c01318a1e23836b949942db14d4811246fdae2f41df9f0dcd922c63bc6,17dacedb6f0379a65160d73c0ae3aa1f03465ae75cb6ae754c7dcb3017af1fbd,17dacedb6f0379a65160d73c0ae3aa1f03465ae75cb6ae754c7dcb3017af1fbd,e5c643f1d8ecc0fd739d0bbe4a1c6c7de2601d86ab0fff74fd89c40908654be5; meta_nocase; classtype: trojan-activity; reference: url,gist.github.com/vulnersCom/65fe44d27d29d7a5de4c176baba45759; reference: url,isc.sans.edu/forums/diary/Widescale+Petya+variant+ransomware+attack+noted/22560/; sid:5003121; rev:1;)

alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[WINDOWS-MALWARE] Petya payload delivery SHA1 hash detected - Open source"; meta_content: "%sagan%",34f917aaba5684fbe56d3c57d48ef2a1aa7cf06d,027cc450ef5f8c5f653329641ec1fed91f694e0d229928963b30f6b0d7d3a745,101cc1cb56c407d5b9149f2c3b8523350d23ba84,a809a63bc5e31670ff117d838522dec433f74bee,d5bf3f100e7dbcc434d7c58ebf64052329a60fc2,aba7aa41057c8a6b184ba5776c20f7e8fc97c657,bec678164cedea578a7aff4589018fa41551c27f,078de2dc59ce59f503c63bd61f1ef8353dc7cf5f,0ff07caedad54c9b65e5873ac2d81b3126754aac,51eafbb626103765d3aedfd098b94d0e77de1196,82920a2ad0138a2a8efc744ae5849c6dde6b435d,1b83c00143a1bb2bf16b46c01f36d53fb66f82b5,7ca37b86f4acc702f108449c391dd2485b5ca18c,2bc182f04b935c7e358ed9c9e6df09ae6af47168,9288fb8e96d419586fc8c595dd95353d48e8a060,736752744122a0b5e
cdc8; meta_nocase; classtype: trojan-activity; reference: url,gist.github.com/vulnersCom/65fe44d27d29d7a5de4c176baba45759; reference: url,isc.sans.edu/forums/diary/Widescale+Petya+variant+ransomware+attack+noted/22560/; sid:5003122; rev:1;)

alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[WINDOWS-MALWARE] Petya payload delivery MD5 hash detected - Open source"; meta_content: "%sagan%",71b6a493388e7d0b40c83ce903bc6b04,415fe69bf32634ca98fa07633f4118e1,0487382a4daf8eb9660f1c67e30f8b25,a1d5895f85751dfe67d19cccb51b051a; meta_nocase; classtype: trojan-activity; reference: url,gist.github.com/vulnersCom/65fe44d27d29d7a5de4c176baba45759; reference: url,isc.sans.edu/forums/diary/Widescale+Petya+variant+ransomware+attack+noted/22560/; sid:5003123; rev:1;)

alert any $EXTERNAL_NET any -> $HOME_NET any (msg: "[WINDOWS-MALWARE] Petya detected by filename - Open source"; meta_content: "%sagan%",myguy.xls,myguy.exe,BCA9D6.EXE,Order-20062017.doc,myguy.xls.hta; meta_nocase; classtype: trojan-activity; reference: url,gist.github.com/vulnersCom/65fe44d27d29d7a5de4c176baba45759; reference: url,isc.sans.edu/forums/diary/Widescale+Petya+variant+ransomware+attack+noted/22560/; sid:5003124; rev:1;)


Fix suggest by @MrAdz350

If you can boot to a Windows ISO prior to Frist reboot you can use bootrec tool to prevent MBR overwriting as per https://neosmart.net/wiki/fix-mbr

Information about MBRFilter

Just correlating all the useful information I can find with regards to the latest Petya Ransomware attack.



<Ignored Process>
 rundll32.exe C:\027cc450ef5f8c5f653329641ec1fed91f694e0d229928963b30f6b0d7d3a745.bin.dll",#1" (PID: 2880)
 cmd.exe " /TR "%WINDIR%\system32\shutdown.exe /r /f" /ST 07:45" (PID: 2724) 
 schtasks.exe " /TR "%WINDIR%\system32\shutdown.exe /r /f" /ST 07:45" (PID: 2720) 
 FE04.tmp %TEMP%\FE04.tmp" \\.\pipe\{E532AB34-D5C5-4AA8-9511-A05572AE75BC}" (PID: 1968) 
 dllhost.dat %WINDIR%\027cc450ef5f8c5f653329641ec1fed91f694e0d229928963b30f6b0d7d3a745.bin.dll",#1 10 "%OSUSER%-PC\%OSUSER%:123456"" (PID: 2512) 1/59 Seen in another context
 cmd.exe /c wevtutil cl Setup & wevtutil cl System & wevtutil cl Security & wevtutil cl Application & fsutil usn deletejournal /D C: (PID: 2072) 
 wevtutil.exe wevtutil cl Setup (PID: 2204) 
 wevtutil.exe wevtutil cl System (PID: 2128) 
 wevtutil.exe wevtutil cl Security (PID: 4016) 
 wevtutil.exe wevtutil cl Application (PID: 3988) 
 fsutil.exe fsutil usn deletejournal /D C: (PID: 1368) 
 shutdown.exe %WINDIR%\system32\shutdown.exe" /r /f" (PID: 2796)


Petya ransomware successful in spreading because it combines both a client-side attack (CVE-2017-0199) and a network based threat (MS17-010)






Another good analysis from Kaspersky

How does the ransomware spread?

To capture credentials for spreading, the ransomware uses custom tools, a la Mimikatz. These extract credentials from the lsass.exe process. After extraction, credentials are passed to PsExec tools or WMIC for distribution inside a network.

Other observed infection vectors include:

  • A modified EternalBlue exploit, also used by WannaCry.
  • The EternalRomance exploit – a remote code execution exploit targeting Windows XP to Windows 2008 systems over TCP port 445 (Note: patched with MS17-010).
  • An attack against the update mechanism of a third-party Ukrainian software product called MeDoc.

IMPORTANT: A single infected system on the network possessing administrative credentials is capable of spreading this infection to all the other computers through WMI or PSEXEC.

Schroedinger’s Pet(ya)


Cloaking Itself in Legitimate Code

Petya uses memory injection as an evasive technique to bypass existing defenses. Attackers often use this method to hide in legitimate processes on the endpoint by injecting malicious code into the memory of non-malicious applications. Sometimes referred to as fileless malware, these threats avoid being detected by file-based detection tools, as the malicious code manipulates the memory stack to achieve malicious actions without actually placing the malicious program on the file system.

In the case of Petya, the executable creates another instance of itself and injects decrypted code into it.





UIWIX Ransomware

Published / by jeff / Leave a Comment

It was just a matter of time until other organisations or individuals followed the path set by WannaCry last weekend.

Seems there is another variant of ransomware doing the rounds which is exploiting the same loop hole as WannaCry is using port 445 to enumerate and infect other machines on your internal and then external networks.  It is exploiting the same SMB vulnerability (MS17-010).

Mitigation – Just need to  make sure you have the latest updates from microsoft.

If you see traffic to these domains, its likely not good!