Multiple vulnerabilities in Nextcloud Server



Published: 2020-05-18
Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2020-8154
CVE-2020-8155
CWE-ID CWE-79
Exploitation vector Network
Public exploit N/A
Vulnerable software
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Nextcloud Server
Client/Desktop applications / Messaging software

Vendor Nextcloud

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Authorization bypass through user-controlled key

EUVDB-ID: #VU27957

Risk: Medium

CVSSv3.1: 4.6 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-8154

CWE-ID: N/A

Exploit availability: No

Description

The vulnerability allows a remote attacker to wipe devices of other users.

The vulnerability exists due to insecure direct object reference in Nextcloud Server. A remote attacker can send specially crafted request directory to the affected endpoint and remotely wipe devices of other users.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Nextcloud Server: 18.0.0 - 18.0.2

External links

http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00037.html
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00038.html
http://hackerone.com/reports/819807
http://nextcloud.com/security/advisory/?id=NC-SA-2020-018


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Cross-site scripting

EUVDB-ID: #VU27958

Risk: Low

CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-8155

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data within a third-party library in Files PDF viewer for Nextcloud Server. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Nextcloud Server: 18.0.0 - 18.0.2

External links

http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00037.html
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00038.html
http://nextcloud.com/security/advisory/?id=NC-SA-2020-019


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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