MAR-10219351.r1.v2 – SamSam1

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This document is marked TLP:WHITE. Disclosure is not limited. Sources may use TLP:WHITE when information carries minimal or no foreseeable risk of misuse, in accordance with applicable rules and procedures for public release. Subject to standard copyright rules, TLP:WHITE information may be distributed without restriction. For more information on the Traffic Light Protocol, see http://www.us-cert.gov/tlp.

Description

Two (2) artifacts were submitted for analysis. The analysis indicates that these files are ransomware.

For a downloadable copy of IOCs, see:

• MAR-10219351.r1.v2.stix

Submitted Files (2)

5d65ebdde1aef8f23114f95454287e7410965288f144d880ece2a2b8c3128645 (prelecturedexe.exe)

d8d919d884b86e4d5977598bc9d637ed53e21d5964629d0427077e08ddbcba68 (proteusdlll.dll)

5d65ebdde1aef8f23114f95454287e7410965288f144d880ece2a2b8c3128645

Tags

ransomwaretrojan

Details

Antivirus

Yara Rules

No matches found.

ssdeep Matches

No matches found.

PE Metadata

PE Sections

Packers/Compilers/Cryptors

Process List

Relationships

Description

This file is a 32-bit Windows executable. The file has been identified as ransomware written in C Sharp (C#). It contains a namespace named "prelecturedexe" and a class named "Program."

This ransomware is invoked using the following command-line format:

-- Begin command format --

prelecturedexe.exe <argv0> <argv1> <argv2> <argv3>

-- End command format --

The execution will quit if 4 arguments are not used.

This ransomware uses Advanced Encryption Standard (AES) encryption. When executed, it uses a command-line argument <argv0> as a component for the AES Rijndael Key and initialization vector (IV). <argv1> <argv2> <argv3> are files and directories to be encrypted/decrypted.

It reads a file named "*.nike2018" in the same directory where this executable resides. If the file "*.nike2018" does not exist, the execution quits. It removes "*.nike2018" after it reads the file content.

d8d919d884b86e4d5977598bc9d637ed53e21d5964629d0427077e08ddbcba68

Tags

ransomwaretrojan

Details

Antivirus

Yara Rules

No matches found.

ssdeep Matches

No matches found.

PE Metadata

PE Sections

Packers/Compilers/Cryptors

Process List

Relationships

Description

This dynamic link library (DLL) contains functions used by the ransomware "prelecturedexe.exe" (222d7fde37ae344824a97087d473cdcd).

It contains a namespace named "proteusdlll" and a class named "Class1."

It contains functions to generate the AES Rijndael Key and IV, function to create the Rijndael decryptor and function to encrypt/decrypt victim's files.

The AES Rijndael Key and IV is generated from the following predefined bytes and the first command line argument <argv0>.    

-- Begin predefined bytes to generate Rijndael Key and IV --

0x49
0x76
0x61
0x6E
0x20
0x4D
0x65
0x64
0x76
0x65
0x64
0x65
0x76

-- End predefined bytes to generate Rijndael Key and IV --

NCCIC would like to remind users and administrators to consider using the following best practices to strengthen the security posture of their organization's systems. Any configuration changes should be reviewed by system owners and administrators prior to implementation to avoid unwanted impacts.

• Maintain up-to-date antivirus signatures and engines.
• Keep operating system patches up-to-date.
• Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
• Restrict users' ability (permissions) to install and run unwanted software applications. Do not add users to the local administrators group unless required.
• Enforce a strong password policy and implement regular password changes.
• Exercise caution when opening e-mail attachments even if the attachment is expected and the sender appears to be known.
• Enable a personal firewall on agency workstations, configured to deny unsolicited connection requests.
• Disable unnecessary services on agency workstations and servers.
• Scan for and remove suspicious e-mail attachments; ensure the scanned attachment is its "true file type" (i.e., the extension matches the file header).
• Monitor users' web browsing habits; restrict access to sites with unfavorable content.
• Exercise caution when using removable media (e.g., USB thumbdrives, external drives, CDs, etc.).
• Scan all software downloaded from the Internet prior to executing.
• Maintain situational awareness of the latest threats and implement appropriate ACLs.

Additional information on malware incident prevention and handling can be found in NIST's Special Publication 800-83, Guide to Malware Incident Prevention & Handling for Desktops and Laptops.

• 1-888-282-0870
• NCCICCustomerService@us-cert.gov (UNCLASS)
• us-cert@dhs.sgov.gov (SIPRNET)
• us-cert@dhs.ic.gov (JWICS)

NCCIC continuously strives to improve its products and services. You can help by answering a very short series of questions about this product at the following URL: https://us-cert.gov/forms/feedback/

What is a MIFR? A Malware Initial Findings Report (MIFR) is intended to provide organizations with malware analysis in a timely manner. In most instances this report will provide initial indicators for computer and network defense. To request additional analysis, please contact US-CERT and provide information regarding the level of desired analysis.

What is a MAR? A Malware Analysis Report (MAR) is intended to provide organizations with more detailed malware analysis acquired via manual reverse engineering. To request additional analysis, please contact US-CERT and provide information regarding the level of desired analysis.

Can I edit this document? This document is not to be edited in any way by recipients. All comments or questions related to this document should be directed to the NCCIC at 1-888-282-0870 or soc@us-cert.gov.

Can I submit malware to NCCIC? Malware samples can be submitted via three methods:

• Web: https://malware.us-cert.gov
• E-Mail: submit@malware.us-cert.gov
• FTP: ftp.malware.us-cert.gov (anonymous)

NCCIC encourages you to report any suspicious activity, including cybersecurity incidents, possible malicious code, software vulnerabilities, and phishing-related scams. Reporting forms can be found on US-CERT's homepage at www.us-cert.gov.