CVE-2017-5493

WordPress Core < 4.7.1 - Weak Multi-Site Activation Key for User and Site Signup

2017-01-11 00:00

Strategic Overview

Status: Patched in 3.7.17
Affected Core: WordPress 4.7
Affected Version: 3.7 – 4.7.0 · 12 branches
CVSS: 5.3Medium
Weakness type: CWE-338 · Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
CVE: CVE-2017-5493

At a glance

CVE-2017-5493 is a medium-severity Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) vulnerability in the WordPress 4.7 WordPress release line, affecting 3.7 – 4.7.0 · 12 branches. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.7.17; sites on affected versions should update now. Disclosed January 2017, reported by Jack.

Vulnerability Overview

wp-includes/ms-functions.php in the Multisite WordPress API in WordPress before 4.7.1 does not properly choose random numbers for keys, which makes it easier for remote attackers to bypass intended access restrictions via a crafted (1) site signup or (2) user signup.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-338: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.

Remediation

Update to one of the following versions, or a newer patched version: 3.7.17, 3.8.17, 3.9.15, 4.0.14, 4.1.14, 4.2.11, 4.3.7, 4.4.6, 4.5.5, 4.6.2, 4.7.1

How does WordSec protect against this?

The fix is the thing that ends this: updating to 3.7.17 is the step that ends it.

Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2017-5493 https://www.wordfence.com/threat-intel/vulnerabilities/id/14b7fd1e-6e2d-49bb-8492-b072afeebd88 https://nvd.nist.gov/vuln/detail/CVE-2017-5493

Related records

Other vulnerabilities in WordPress 4.7

CVSS Vector

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityLow
IntegrityNone
AvailabilityNone

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