VDB-185387 · CVE-2021-39223 · GHSA-rjcc-4cgj-6v93

Nextcloud up to 3.8.5/4.2.2 shared.txt information disclosure

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
3.6	$0-$5k	0.00

A vulnerability was found in Nextcloud up to 3.8.5/4.2.2 (Cloud Software) and classified as problematic. This issue affects some unknown processing of the file /files/$username/Myfolder/Mysubfolder/shared.txt. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality.

The weakness was disclosed 10/26/2021 as GHSA-rjcc-4cgj-6v93. It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2021-39223 since 08/16/2021. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

By approaching the search of inurl:files/$username/Myfolder/Mysubfolder/shared.txt it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 3.8.6 or 4.2.3 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Productinfo

Type

Cloud Software

Name

Nextcloud

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.6

VulDB Base Score: 2.6
VulDB Temp Score: 2.5
VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA Base Score: 4.8
CNA Vector (GitHub, Inc.): 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / CWE-266
ATT&CK: T1592

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined
Google Hack: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Nextcloud 3.8.6/4.2.3
Patch: github.com

Timelineinfo

08/16/2021 🔍
10/26/2021 +71 days 🔍
10/26/2021 +0 days 🔍
10/30/2021 +4 days 🔍

Sourcesinfo

Advisory: GHSA-rjcc-4cgj-6v93
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-39223 (🔍)

Entryinfo

Created: 10/26/2021 01:36 PM
Updated: 10/30/2021 11:54 AM
Changes: 10/26/2021 01:36 PM (51), 10/30/2021 11:54 AM (2)
Complete: 🔍