Rewterz penetration testing services help organizations determine if a cyber attacker can gain access to their critical assets while giving them detailed insights of the overall business impact of a cyber attack.
Before Rewterz got its start, the market was in dire need of a specialized and dedicated information security company. It was nearly impossible for businesses to find a trustworthy provider that could truly cover all of their bases. We wanted to meet this need, giving companies across the globe a chance to get ahead while knowing that their data is in good hands.
Rewterz penetration testing services help organizations determine if a cyber attacker can gain access to their critical assets while giving them detailed insights of the overall business impact of a cyber attack.
Before Rewterz got its start, the market was in dire need of a specialized and dedicated information security company. It was nearly impossible for businesses to find a trustworthy provider that could truly cover all of their bases. We wanted to meet this need, giving companies across the globe a chance to get ahead while knowing that their data is in good hands.
WannaCry is a family of Ransomware which when executed, encrypts certain file types on the system. The user must pay a ransom to the attacker if they want their files to be decrypted.
This ransomware uses the EternalBlue exploit (MS17-010 Echo Response – SMB Vulnerability). The attackers have used the publicly available exploit code and embedded it in the dropper of the ransomware. The malware’s initial vector seems to be spam emails. The malware, on execution, connects to the IPC$ tree and attempts a transaction on FID 0, triggers the vulnerability, and then exploits it. The malware generates a random set of IP addresses for propagation
The Malware is executed using a main dropper and a sub dropper. The main dropper is embedded with the shell code needed for propagation. It also contains the sub dropper which executes the encryption process.
The sub dropper contains multiple components in the form of a password-protected ZIP file in its Resource section. The password is hardcoded “WNcry@2ol7”. The components of the sub dropper perform other functions on the system.
Given below is an example ZIP.
The dropper installs itself as a service called MSSECSVC2.0 with description “Microsoft Security Service (2.0)” as a restart mechanism. Once the service is started, it generated its random list of IP addresses to target.
The dropper uses the command line below to remove any existing shadow volumes and backups:
Cmd /c vssadmin delete shadows /all /quiet & wmic shadowcopy delete & bcdedit /set {default} bootstatuspolicy ignoreallfailures & bcdedit /set {default} recoveryenabled no & wbadmin delete catalog -quiet
The various components dropped to disk are listed below:
Once the system files are encrypted, the ransomware drops this message:
The desktop wallpaper is also changed to this:
The Folder containing the encrypted files also contains a text version of this message demanding a ransom for their decryption.
The main dropper creates a random set of IP addresses which are not limited to the local network. This means that the malware may attack devices sharing the same network, as well as devices across the Internet if they allow NetBIOS packets from outside networks.
This is why the attack has such a wide-spread impact and many affected users are unsure about the initial vector of the infection.
Once a device with an open NetBIOS port is found, the malware will send three NETBIOS session setup packets to it. This communication is followed by the transfer of a sub dropper.
Among the files transferred to the attacked system is a ZIP file containing Tor browser binaries which is used to access the Onion URLs in use by the malware to collect payments.
The Payment is collected through Bitcoin. The following addresses are found in the samples
The sub dropper infects files with specific extensions on the local machine, any removable drive connected to it, and any network share mounted locally.
If you think you are a victim of a cyber-security attack. Immediately send an email to info@rewterz.com for a rapid response.