DoS flaw lets attackers crash NodeJS apps via DNS lookups

This week, NodeJS project has released fixes for a DoS vulnerability, CVE-2020-8277, that could be triggered via DNS requests.

An attacker could exploit this flaw in a Node.js app that enabled users to make DNS requests to cause a Denial of Service (DoS) condition.

By performing DNS lookups for a hostname or domain of the attacker’s choice that returns exceptionally large responses, the vulnerable Node.js application could be crashed.

“A Node.js application that allows an attacker to trigger a DNS request for a host of their choice could trigger a Denial of service by getting the application to resolve a DNS record with a larger number of responses,” states NodeJS security advisory.

At the time of writing, it appears, the HackerOne bug report for this vulnerability is still awaiting public disclosure.

The flaw impacts following Node.js versions:

• Versions 12.16.3 and higher on the 12.x release line
• Versions 14.13.0 and higher on the 14.x release line
• All versions of the 15.x release line

Patches released for different branches

The NodeJS project has issued fixes for CVE-2020-8277 in the following versions:

• Node.js v12.19.1 (LTS)
• Node.js v14.15.1 (LTS)
• Node.js v15.2.1 (Current)

Users are advised to upgrade to fixed versions immediately to safeguard their Node.js applications against vulnerablilities like these.

About the author

Ax Sharma

Ax Sharma is an Indian-origin British security researcher, journalist and TV subject matter expert with a focus on malware analysis and cybercrime investigations. His areas of interest include open source software security, threat intel analysis, and reverse engineering. Frequently featured by leading media outlets like the BBC, Channel 5, Fortune, WIRED, The Register, among others, Ax is an active community member of the OWASP Foundation and the British Association of Journalists (BAJ).

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