Denial of Service (DoS)

Affecting js-yaml package, versions <1.5.0

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Overview

js-yaml is a human-friendly data serialization language.

Affected versions of this package are vulnerable to Denial of Service (DoS). It's possible to abuse aliases to create an exponential tree of nodes consisting of collections that each have multiple references. When such a tree is used as the key of a mapping it is then converted to a JS object, which is then parsed by JSON.stringify(), which causes the process to run out of memory creating the string.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade js-yaml to version 1.5.0 or higher.

References

CVSS Score

5.9
medium severity
  • Attack Vector
    Network
  • Attack Complexity
    High
  • Privileges Required
    None
  • User Interaction
    None
  • Scope
    Unchanged
  • Confidentiality
    None
  • Integrity
    None
  • Availability
    High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/RL:O
Credit
eemeli
CWE
CWE-400
Snyk ID
SNYK-JS-JSYAML-174117
Disclosed
04 Apr, 2019
Published
05 Apr, 2019