CVE-2021-22925 : What You Need to Know

A vulnerability in curl versions 7.7 to 7.77.0 could allow sensitive data exposure to servers via uninitialized stack-based buffer data.

Understanding CVE-2021-22925

This CVE identifies a flaw in the

-t

command line option, also known as

CURLOPT_TELNETOPTIONS

in libcurl, that could potentially leak internal information to servers.

What is CVE-2021-22925?

The vulnerability in curl can result in exposing sensitive data by passing uninitialized stack buffer data to the server, due to an error in parsing the

NEW_ENV

variables. This could lead to data leakage during interactions with TELNET servers.

The Impact of CVE-2021-22925

The impact of this vulnerability is significant as it allows servers to access confidential information sent through clear-text network protocols, potentially compromising data confidentiality and integrity.

Technical Details of CVE-2021-22925

The technical details involve a flaw in the option parser for sending

NEW_ENV

variables in libcurl. The vulnerability arises from the incorrect usage of

sscanf()

during parsing, leading to the disclosure of uninitialized data from the stack buffer.

Vulnerability Description

The vulnerability stems from curl's mishandling of the parsing of

NEW_ENV

variables, enabling the leakage of uninitialized stack buffer data to servers through TELNET interactions.

Affected Systems and Versions

The vulnerability affects curl versions 7.7 to 7.77.0, potentially impacting systems utilizing these versions during TELNET sessions.

Exploitation Mechanism

Exploiting this vulnerability involves sending crafted variable=content pairs to TELNET servers, triggering the flawed option parser in libcurl and exposing sensitive data during network communication.

Mitigation and Prevention

To mitigate the CVE-2021-22925 vulnerability, immediate action and long-term security practices are crucial.

Immediate Steps to Take

Users are advised to update curl to versions beyond 7.77.0 to eliminate the vulnerability. Additionally, avoiding TELNET communications or utilizing encrypted channels can reduce the risk of data exposure.

Long-Term Security Practices

Implementing secure data handling practices, regular security assessments, and fostering a security-conscious culture can enhance overall resilience against similar vulnerabilities.

Patching and Updates

Regularly monitoring for security patches and staying informed about software updates from trusted sources like curl's official website is essential for maintaining a secure environment.