CVE-2021-41569 : Exploit Details and Defense Strategies

SAS/Intrnet 9.4 build 1520 and earlier versions contain a Local File Inclusion vulnerability that allows users to access and retrieve files from the host operating system.

Understanding CVE-2021-41569

This CVE involves a critical security issue in SAS/Intrnet 9.4 build 1520 and prior versions, enabling unauthorized file access and potential exploitation of the system.

What is CVE-2021-41569?

SAS/Intrnet 9.4 build 1520 and earlier are susceptible to Local File Inclusion, permitting end-users of the application to access a specific program that contains user-controlled macro variables, potentially leading to unauthorized functions execution.

The Impact of CVE-2021-41569

The vulnerability can be exploited by users to bypass user-controlled variables, execute additional functions, and fetch files from the host OS, potentially leading to unauthorized access and data leakage.

Technical Details of CVE-2021-41569

This section delves into the technical specifics of the vulnerability.

Vulnerability Description

SAS/Intrnet 9.4 build 1520 allows Local File Inclusion through user-controlled macro variables, enabling users to execute functions not originally part of the library, including file retrieval from the host OS.

Affected Systems and Versions

Product: SAS/Intrnet 9.4 build 1520 and earlier
Vendor: SAS
Versions: All versions prior to build 1520

Exploitation Mechanism

Users exploit the vulnerability by manipulating macro variables in the appstart.sas file, accessing the sample.webcsf1.sas program, and executing unauthorized functions that can retrieve files from the host OS.

Mitigation and Prevention

Steps to mitigate the risks associated with CVE-2021-41569.

Immediate Steps to Take

Update SAS/Intrnet to the latest version to patch the vulnerability
Implement proper input validation and sanitization techniques
Restrict access to critical system files and directories

Long-Term Security Practices

Regularly review and update software and security configurations
Conduct security training for developers and users on secure coding practices

Patching and Updates

Apply security patches provided by SAS promptly
Monitor official channels for any security advisories and updates