CVE-2021-0204 : Exploit Details and Defense Strategies

A sensitive information disclosure vulnerability in the delta-export configuration utility (dexp) of Juniper Networks Junos OS allows a locally authenticated shell user to access sensitive information, including password hashes of local users. This vulnerability affects multiple versions of Junos OS.

Understanding CVE-2021-20657

This CVE highlights a local privilege escalation vulnerability in SUID binaries within Junos OS.

What is CVE-2021-20657?

The CVE-2021-20657 vulnerability in Juniper Networks Junos OS allows locally authenticated users to create and read database files, potentially leading to unauthorized access to sensitive information, including password hashes.

The Impact of CVE-2021-20657

With a high CVSS base score of 7.8, the vulnerability poses a severe threat, enabling attackers with local shell access to elevate their privileges and access sensitive data.

Technical Details of CVE-2021-20657

This section provides detailed technical insights into the vulnerability.

Vulnerability Description

The vulnerability allows a local privileged user to exploit the dexp utility to access sensitive database files with root privileges, posing a significant security risk.

Affected Systems and Versions

Multiple versions of Junos OS, ranging from 15.1 to 20.2, are impacted by this vulnerability, before specific patched releases.

Exploitation Mechanism

While Juniper SIRT has not detected any malicious exploitation, the potential for unauthorized access to sensitive information by local privileged users exists.

Mitigation and Prevention

Addressing the CVE-2021-20657 vulnerability is crucial to secure affected systems and prevent unauthorized access.

Immediate Steps to Take

Implement access controls and restrict CLI and Junos OS shell access to trusted administrative networks to mitigate the risk of exploitation.

Long-Term Security Practices

Continuously monitor security advisories and promptly apply software updates and patches released by Juniper Networks to ensure system security.

Patching and Updates

Juniper Networks has released updated software versions that resolve the vulnerability for a range of affected Junos OS versions, including subsequent releases.