VDB-224644 · CVE-2023-28835 · GHSA-7w2p-rp9m-9xp9

Nextcloud Server up to 24.0.9/25.0.3 Share weak prng

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.
4.8	$0-$5k	0.00

A vulnerability has been found in Nextcloud Server up to 24.0.9/25.0.3 (Cloud Software) and classified as problematic. This vulnerability affects an unknown function of the component Share Handler. The manipulation with an unknown input leads to a weak prng vulnerability. The CWE definition for the vulnerability is CWE-338. The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong. As an impact it is known to affect confidentiality. CVE summarizes:

Nextcloud server is an open source home cloud implementation. In affected versions the generated fallback password when creating a share was using a weak complexity random number generator, so when the sharer did not change it the password could be guessable to an attacker willing to brute force it. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. This issue only affects users who do not have a password policy enabled, so enabling a password policy is an effective mitigation for users unable to upgrade.

The weakness was shared 03/31/2023 as GHSA-7w2p-rp9m-9xp9. The advisory is shared for download at github.com. This vulnerability was named CVE-2023-28835 since 03/24/2023. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1600.001.

Upgrading to version 24.0.10 or 25.0.4 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

Vendor

Nextcloud

Name

Server

Version

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.8

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CNA Base Score: 3.5
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: Weak prng
CWE: CWE-338 / CWE-331 / CWE-330
CAPEC: 🔍
ATT&CK: 🔍

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

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: Server 24.0.10/25.0.4
Patch: github.com

Timelineinfo

03/24/2023 🔍
03/31/2023 +6 days 🔍
03/31/2023 +0 days 🔍
04/20/2023 +20 days 🔍

Sourcesinfo

Advisory: GHSA-7w2p-rp9m-9xp9
Status: Confirmed

CVE: CVE-2023-28835 (🔍)

Entryinfo

Created: 03/31/2023 09:06
Updated: 04/20/2023 18:19
Changes: 03/31/2023 09:06 (53), 04/20/2023 18:19 (11)
Complete: 🔍