SB2021110201 - Improper input validation in Unicode Bidirectional Algorithm

Description

This security bulletin contains information about 1 vulnerability.

1) Input validation error (CVE-ID: CVE-2021-42574)

The vulnerability allows an attacker to bypass certain security checks.

The vulnerability exists in the Bidirectional Algorithm in the Unicode Specification. It permits the visual reordering of characters via control sequences, which can be used to craft source code that renders different logic than the logical ordering of tokens ingested by compilers and interpreters.

An attacker can leverage this behavior to encode source code for compilers accepting Unicode such that targeted vulnerabilities are introduced invisibly to human reviewers.

Remediation

Cybersecurity Help is not aware of any official remediation provided by the vendor.

References

• http://www.openwall.com/lists/oss-security/2021/11/01/1
• http://www.openwall.com/lists/oss-security/2021/11/01/4
• http://www.openwall.com/lists/oss-security/2021/11/01/5
• http://www.openwall.com/lists/oss-security/2021/11/01/6
• https://github.blog/changelog/2021-10-31-warning-about-bidirectional-unicode-text/