5.3
MEDIUM
CVE-2021-21323
Brave Tor DNS Leak Vulnerability
Description

Brave is an open source web browser with a focus on privacy and security. In Brave versions 1.17.73-1.20.103, the CNAME adblocking feature added in Brave 1.17.73 accidentally initiated DNS requests that bypassed the Brave Tor proxy. Users with adblocking enabled would leak DNS requests from Tor windows to their DNS provider. (DNS requests that were not initiated by CNAME adblocking would go through Tor as expected.) This is fixed in Brave version 1.20.108

INFO

Published Date :

Feb. 23, 2021, 11:15 p.m.

Last Modified :

March 1, 2021, 4:14 p.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

1.4

Exploitability Score :

3.9
Affected Products

The following products are affected by CVE-2021-21323 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Brave brave
: Total Affected Vendor : 1 | Products : 1
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-21323.

URL Resource
https://github.com/brave/brave-browser/issues/13527 Patch Third Party Advisory
https://github.com/brave/brave-browser/security/advisories/GHSA-mqjf-9x5g-2rv6 Third Party Advisory
https://github.com/brave/brave-core/commit/12fe321eaad8acc1cbd1d70b4128f687777bcf15 Patch Third Party Advisory
https://github.com/brave/brave-core/pull/7769 Patch Third Party Advisory
https://hackerone.com/reports/1077022 Permissions Required Third Party Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-21323 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-21323 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Initial Analysis by [email protected]

    Mar. 01, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:P/I:N/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
    Changed Reference Type https://github.com/brave/brave-browser/issues/13527 No Types Assigned https://github.com/brave/brave-browser/issues/13527 Patch, Third Party Advisory
    Changed Reference Type https://github.com/brave/brave-browser/security/advisories/GHSA-mqjf-9x5g-2rv6 No Types Assigned https://github.com/brave/brave-browser/security/advisories/GHSA-mqjf-9x5g-2rv6 Third Party Advisory
    Changed Reference Type https://github.com/brave/brave-core/commit/12fe321eaad8acc1cbd1d70b4128f687777bcf15 No Types Assigned https://github.com/brave/brave-core/commit/12fe321eaad8acc1cbd1d70b4128f687777bcf15 Patch, Third Party Advisory
    Changed Reference Type https://github.com/brave/brave-core/pull/7769 No Types Assigned https://github.com/brave/brave-core/pull/7769 Patch, Third Party Advisory
    Changed Reference Type https://hackerone.com/reports/1077022 No Types Assigned https://hackerone.com/reports/1077022 Permissions Required, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:a:brave:brave:*:*:*:*:*:*:*:* versions from (including) 1.17.73 up to (including) 1.20.103
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-21323 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-21323 weaknesses.

CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client CAPEC-59: Session Credential Falsification through Prediction Session Credential Falsification through Prediction CAPEC-60: Reusing Session IDs (aka Session Replay) Reusing Session IDs (aka Session Replay) CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-116: Excavation Excavation CAPEC-169: Footprinting Footprinting CAPEC-224: Fingerprinting Fingerprinting CAPEC-285: ICMP Echo Request Ping ICMP Echo Request Ping CAPEC-287: TCP SYN Scan TCP SYN Scan CAPEC-290: Enumerate Mail Exchange (MX) Records Enumerate Mail Exchange (MX) Records CAPEC-291: DNS Zone Transfers DNS Zone Transfers CAPEC-292: Host Discovery Host Discovery CAPEC-293: Traceroute Route Enumeration Traceroute Route Enumeration CAPEC-294: ICMP Address Mask Request ICMP Address Mask Request CAPEC-295: Timestamp Request Timestamp Request CAPEC-296: ICMP Information Request ICMP Information Request CAPEC-297: TCP ACK Ping TCP ACK Ping CAPEC-298: UDP Ping UDP Ping CAPEC-299: TCP SYN Ping TCP SYN Ping CAPEC-300: Port Scanning Port Scanning CAPEC-301: TCP Connect Scan TCP Connect Scan CAPEC-302: TCP FIN Scan TCP FIN Scan CAPEC-303: TCP Xmas Scan TCP Xmas Scan CAPEC-304: TCP Null Scan TCP Null Scan CAPEC-305: TCP ACK Scan TCP ACK Scan CAPEC-306: TCP Window Scan TCP Window Scan CAPEC-307: TCP RPC Scan TCP RPC Scan CAPEC-308: UDP Scan UDP Scan CAPEC-309: Network Topology Mapping Network Topology Mapping CAPEC-310: Scanning for Vulnerable Software Scanning for Vulnerable Software CAPEC-312: Active OS Fingerprinting Active OS Fingerprinting CAPEC-313: Passive OS Fingerprinting Passive OS Fingerprinting CAPEC-317: IP ID Sequencing Probe IP ID Sequencing Probe CAPEC-318: IP 'ID' Echoed Byte-Order Probe IP 'ID' Echoed Byte-Order Probe CAPEC-319: IP (DF) 'Don't Fragment Bit' Echoing Probe IP (DF) 'Don't Fragment Bit' Echoing Probe CAPEC-320: TCP Timestamp Probe TCP Timestamp Probe CAPEC-321: TCP Sequence Number Probe TCP Sequence Number Probe CAPEC-322: TCP (ISN) Greatest Common Divisor Probe TCP (ISN) Greatest Common Divisor Probe CAPEC-323: TCP (ISN) Counter Rate Probe TCP (ISN) Counter Rate Probe CAPEC-324: TCP (ISN) Sequence Predictability Probe TCP (ISN) Sequence Predictability Probe CAPEC-325: TCP Congestion Control Flag (ECN) Probe TCP Congestion Control Flag (ECN) Probe CAPEC-326: TCP Initial Window Size Probe TCP Initial Window Size Probe CAPEC-327: TCP Options Probe TCP Options Probe CAPEC-328: TCP 'RST' Flag Checksum Probe TCP 'RST' Flag Checksum Probe CAPEC-329: ICMP Error Message Quoting Probe ICMP Error Message Quoting Probe CAPEC-330: ICMP Error Message Echoing Integrity Probe ICMP Error Message Echoing Integrity Probe CAPEC-472: Browser Fingerprinting Browser Fingerprinting CAPEC-497: File Discovery File Discovery CAPEC-508: Shoulder Surfing Shoulder Surfing CAPEC-573: Process Footprinting Process Footprinting CAPEC-574: Services Footprinting Services Footprinting CAPEC-575: Account Footprinting Account Footprinting CAPEC-576: Group Permission Footprinting Group Permission Footprinting CAPEC-577: Owner Footprinting Owner Footprinting CAPEC-616: Establish Rogue Location Establish Rogue Location CAPEC-643: Identify Shared Files/Directories on System Identify Shared Files/Directories on System CAPEC-646: Peripheral Footprinting Peripheral Footprinting CAPEC-651: Eavesdropping Eavesdropping
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.08 }} 0.01%

score

0.33869

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: