Kerala State IT Mission issues advisory on Petya ransomware attack

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Trivandrum: The Kerala State IT Mission has issued an advisory to all departments under the State Government to alert them on a new cyber virus attack named ‘Petya’ believed to be ransomware – a piece of malicious software that shuts down a computer system and then demands an extortionate sum of money to fix the problem.

Unlike other traditional ransomware, Petya does not encrypt files on a targeted system one by one. Instead, Petya reboots victim’s computers and encrypts the hard drive’s master file table (MFT) and rendering the master boot record (MBR) inoperable, restricting access to the full system by seizing information about file names, sizes, and location on the physical disk. Petya replaces the computer’s MBR with its own malicious code that displays the ransom note and leaves computers unable to boot. Like WannaCry, Petya is also exploiting SMBv1 EternalBlue exploit and taking advantage of unpatched Windows machines.

Recommendations

Computer users are advised to kindly take the following preventive measures to protect their computer networks from ransomware infection/attacks:

  • In order to prevent infection, users and organisations are advised to apply patches to Windows systems as mentioned in Microsoft Security Bulletin MS17-010. https://technet.microsoft.com/library/security/MS17-010
  • Maintain updated Antivirus software on all systems.
  • Perform regular backups of all critical information to limit the impact of data or system loss and to help expedite the recovery process. Ideally, this data should be kept on a separate device, and backups should be stored offline.
  • Block SMB ports on Enterprise Edge/perimeter network devices [UDP 137, 138 and TCP 139, 445] or Disable SMBv1. https://support.microsoft.com/en-us/help/2696547
  • Don’t open attachments in unsolicited e-mails, even if they come from people in your contact list, and never click on a URL contained in an unsolicited e-mail, even if the link seems benign. In cases of genuine URLs close out the e-mail and go to the organisation’s website directly through a browser.
  • Restrict execution of Powershell /WSCRIPT/ PSEXEC / WMIC in enterprise environment Ensure installation and use of the latest version (currently v5.0) of PowerShell, with enhanced logging enabled, script block logging, and transcription enabled. Send the associated logs to a centralised log repository for monitoring and analysis.
  • Establish a Sender Policy Framework (SPF), Domain Message Authentication Reporting and Conformance (DMARC), and DomainKeys Identified Mail (DKIM) for your domain, which is an email validation system designed to prevent spam by detecting email spoofing by which most of the ransomware samples successfully reaches the corporate email boxes.
  • Application whitelisting/Strict implementation of Software Restriction Policies (SRP) to block binaries running from %APPDATA%, %PROGRAMDATA% and %TEMP% paths. Ransomware sample drops and executes generally from these locations. Enforce application whitelisting on all endpoint workstations.
  • Deploy web and email filters on the network. Configure these devices to scan for known bad domains, sources, and addresses; block these before receiving and downloading messages. Scan all emails, attachments, and downloads both on the host and at the mail gateway with a reputable antivirus solution.
  • Disable macros in Microsoft Office products. Some Office products allow for the disabling of macros that originate from outside of an organization and can provide a hybrid approach when the organization depends on the legitimate use of macros. For Windows, specific settings can block macros originating from the Internet from running.
  • Configure access controls including file, directory, and network share permissions with least privilege in mind. If a user only needs to read specific files, they should not have write access to those files, directories, or shares.
  • Consider installing Enhanced Mitigation Experience Toolkit, or similar host-level anti-exploitation tools.
  • Block the attachments of file types, exe|pif|tmp|url|vb|vbe|scr|reg|cer|pst|cmd|com|bat|dll|dat|hlp|hta|js|wsf
  • Regularly check the contents of backup files of databases for any unauthorised encrypted contents of data records or external elements, (backdoors /malicious scripts.)
  • Keep the operating system third party applications (MS Office, browsers, browser Plugins) up-to-date with the latest patches.
  • Follow safe practices when browsing the web. Ensure the web browsers are secured enough with appropriate content controls.
  • Network segmentation and segregation into security zones – help protect sensitive information and critical services. Separate administrative network from business processes with physical controls and Virtual Local Area Networks.
  • Disable remote Desktop Connections, employ least-privileged accounts.
  • Ensure integrity of the codes /scripts being used in database, authentication and sensitive systems, Check regularly for the integrity of the information stored in the databases.
  • Restrict users’ abilities (permissions) to install and run unwanted software applications.
  • Employ data-at-rest and data-in-transit encryption.

Individuals or organisations are not encouraged to pay the ransom, as this does not guarantee files will be released.

Kerala IT News

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