CVE-2018-7549 : Exploit Details and Defense Strategies

This CVE involves a crash in the params.c file in zsh versions 5.4.2 and earlier when attempting to copy an empty hash table using typeset -p.

Understanding CVE-2018-7549

This vulnerability was made public on February 27, 2018, and affects zsh versions 5.4.2 and prior.

What is CVE-2018-7549?

In zsh through version 5.4.2, a crash occurs during the copying of an empty hash table, triggered by the typeset -p command.

The Impact of CVE-2018-7549

The vulnerability can lead to a denial of service (DoS) condition due to the crash caused by copying an empty hash table.

Technical Details of CVE-2018-7549

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The crash occurs in the params.c file in zsh version 5.4.2 and earlier when attempting to copy an empty hash table, as shown by the usage of typeset -p.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: zsh version 5.4.2 and earlier

Exploitation Mechanism

The vulnerability is triggered by executing the typeset -p command in zsh versions 5.4.2 and prior, leading to a crash.

Mitigation and Prevention

Protecting systems from CVE-2018-7549 requires specific actions to mitigate the risks.

Immediate Steps to Take

Update zsh to a version beyond 5.4.2 to prevent the crash when copying empty hash tables.
Monitor vendor advisories for patches and updates related to this vulnerability.

Long-Term Security Practices

Regularly update software and dependencies to ensure the latest security patches are applied.
Employ proper input validation and error handling mechanisms in scripts to prevent crashes.

Patching and Updates

Apply patches provided by zsh or relevant vendors to address the vulnerability and prevent potential DoS attacks.