Vulnerability Name:

CVE-2021-32728 (CCN-207808)

Assigned:2021-08-18
Published:2021-08-18
Updated:2022-10-04
Summary:The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.
CVSS v3 Severity:6.5 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)
5.7 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): None
Availibility (A): None
6.5 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)
5.7 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): None
Availibility (A): None
CVSS v2 Severity:4.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:S/C:P/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): Partial
Integrity (I): None
Availibility (A): None
6.8 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:S/C:C/I:N/A:N)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): Complete
Integrity (I): None
Availibility (A): None
Vulnerability Type:CWE-295
Vulnerability Consequences:Obtain Information
References:Source: MITRE
Type: CNA
CVE-2021-32728

Source: XF
Type: UNKNOWN
nextcloud-cve202132728-info-disc(207808)

Source: MISC
Type: Patch, Third Party Advisory
https://github.com/nextcloud/desktop/pull/3338

Source: CCN
Type: Nextcloud GIT Repository
End-to-end encryption device setup did not verify public key

Source: CONFIRM
Type: Exploit, Third Party Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5

Source: MISC
Type: Exploit, Third Party Advisory
https://hackerone.com/reports/1189162

Source: DEBIAN
Type: Third Party Advisory
DSA-4974

Vulnerable Configuration:Configuration 1:
  • cpe:/a:nextcloud:desktop:*:*:*:*:*:*:*:* (Version < 3.3.0)

    • Configuration 2:
  • cpe:/o:debian:debian_linux:10.0:*:*:*:*:*:*:*
  • OR cpe:/o:debian:debian_linux:11.0:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    nextcloud desktop *
    debian debian linux 10.0
    debian debian linux 11.0