CVE-2022-36064 : Exploit Details and Defense Strategies

Shescape is a shell escape package for JavaScript that is impacted by an Inefficient Regular Expression Complexity vulnerability. This vulnerability affects users utilizing Shescape to escape arguments for Unix shells like

Bash

and

Dash

, or any unsupported Unix shell. The vulnerability arises when using the

escape

or

escapeAll

functions with the

interpolation

option set to

true

, leading to Regular Expression Denial of Service (ReDoS) due to polynomial backtracking or quadratic runtime in input string length.

Understanding CVE-2022-36064

Shescape is a shell escape package for JavaScript that has been identified with an Inefficient Regular Expression Complexity vulnerability. This vulnerability can lead to Regular Expression Denial of Service (ReDoS) for users of Shescape under specific conditions.

What is CVE-2022-36064?

The CVE-2022-36064 vulnerability affects Shescape users employing the package to escape arguments for Unix shells like

Bash

and

Dash

, or any unofficial Unix shell. When using the

escape

or

escapeAll

functions with the

interpolation

option set to

true

, attackers can exploit this vulnerability to cause polynomial backtracking or quadratic runtime, resulting in Regular Expression Denial of Service (ReDoS).

The Impact of CVE-2022-36064

The vulnerability can lead to a high impact on availability for affected users. Although confidentiality and integrity impacts are none, the complexity of exploiting the vulnerability is considered high.

Technical Details of CVE-2022-36064

The Technical Details of CVE-2022-36064 include Vulnerability Description, Affected Systems and Versions, and the Exploitation Mechanism.

Vulnerability Description

The vulnerability in Shescape enables attackers to trigger Regular Expression Denial of Service (ReDoS) by exploiting the package's inefficiency in handling specific input scenarios.

Affected Systems and Versions

Users of Shescape versions greater than or equal to 1.5.1 and less than 1.5.10 are impacted by this vulnerability.

Exploitation Mechanism

Attackers can exploit the vulnerable Regular Expressions in Shescape by leveraging the

escape

or

escapeAll

functions with the

interpolation

option set to

true

, causing significant runtime inefficiencies.

Mitigation and Prevention

To address CVE-2022-36064, users can take immediate steps to secure their systems and implement long-term security practices along with timely patching and updates.

Immediate Steps to Take

Enforce a maximum length on input strings to Shescape to reduce the impact of the vulnerability and avoid trying to detect vulnerable input strings to prevent potential ReDoS risks.

Long-Term Security Practices

Establish strict input validation practices and regularly update Shescape to the latest patched versions to mitigate vulnerabilities.

Patching and Updates

Ensure that Shescape is updated to version 1.5.10 or higher to eliminate the Inefficient Regular Expression Complexity vulnerability and protect systems from potential exploitation.