CVE-2021-27342: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-255g-8gjp-2wq6
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CWE-203
Published
Advisory Summary

CVE-2021-27342 is a MODERATE security vulnerability vulnerability (CWE-203: Observable Discrepancy) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.. Remediation is available in the latest vendor maintenance releases.

CVE-2021-27342 at a Glance

CVE Identifier CVE-2021-27342
GHSA Identifier GHSA-255g-8gjp-2wq6
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-203: Observable Discrepancy
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2021-27342

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-27342, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-203: Observable Discrepancy, where the product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

An authentication brute-force protection mechanism bypass in telnetd in D-Link Router model DIR-842 firmware version 3.0.2 allows a remote attacker to circumvent the anti-brute-force cool-down delay period via a timing-based side-channel attack

References

NVD — CVE-2021-27342 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-27342
blog.whtaguy.com/2021/05/d-link-rout... WEB
https://blog.whtaguy.com/2021/05/d-link-router-cve-2021-27342.html
Software Source Repository REPOSITORY
https://github.com/guywhataguy/D-Link-CVE-2021-27342-exploit/blob/main/dlink-telnet-exploit-CVE-2021-27342.py
supportannouncement.us.dlink.com/announcement/public... WEB
https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10225

Frequently Asked Questions

What is CVE-2021-27342?
CVE-2021-27342 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-203: Observable Discrepancy.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2021-27342?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2021-27342?
CVE-2021-27342 is classified under CWE-203: Observable Discrepancy (The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.).
How can I check Maven dependencies for CVE-2021-27342?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-255g-8gjp-2wq6",
  "modified" : "2022-05-24T19:02:38Z",
  "published" : "2022-05-24T19:02:38Z",
  "aliases" : [ "CVE-2021-27342" ],
  "details" : "An authentication brute-force protection mechanism bypass in telnetd in D-Link Router model DIR-842 firmware version 3.0.2 allows a remote attacker to circumvent the anti-brute-force cool-down delay period via a timing-based side-channel attack",
  "severity" : [ ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-27342"
  }, {
    "type" : "WEB",
    "url" : "https://blog.whtaguy.com/2021/05/d-link-router-cve-2021-27342.html"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/guywhataguy/D-Link-CVE-2021-27342-exploit/blob/main/dlink-telnet-exploit-CVE-2021-27342.py"
  }, {
    "type" : "WEB",
    "url" : "https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10225"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-203" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2021-05-17T13:15:00Z"
  }
}