CVE-2020-7787 Improper Authentication

2020-12-0916:45:13

snyk

www.cve.org

cve-2020-7787

improper authentication

react-adal package

jwt token

request url

logical defect

browser storage

adal.js

CVSS3

8.2

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

LOW

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N/E:P/RL:T/RC:R

AI Score

Confidence

High

EPSS

0.005

Percentile

76.7%

JSON

This affects all versions of package react-adal. It is possible for a specially crafted JWT token and request URL can cause the nonce, session and refresh values to be incorrectly validated, causing the application to treat an attacker-generated JWT token as authentic. The logical defect is caused by how the nonce, session and refresh values are stored in the browser local storage or session storage. Each key is automatically appended by ||. When the received nonce and session keys are generated, the list of values is stored in the browser storage, separated by ||, with || always appended to the end of the list. Since || will always be the last 2 characters of the stored values, an empty string (“”) will always be in the list of the valid values. Therefore, if an empty session parameter is provided in the callback URL, and a specially-crafted JWT token contains an nonce value of “” (empty string), then adal.js will consider the JWT token as authentic.

CNA Affected

[
  {
    "product": "react-adal",
    "vendor": "n/a",
    "versions": [
      {
        "lessThan": "unspecified",
        "status": "affected",
        "version": "0",
        "versionType": "custom"
      }
    ]
  }
]