Remote code execution in Cisco Small Business Routers UPnP service



Published: 2021-08-22 | Updated: 2021-09-30
Risk Critical
Patch available NO
Number of vulnerabilities 1
CVE-ID CVE-2021-34730
CWE-ID CWE-121
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
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RV110W Wireless-N VPN Firewall
Hardware solutions / Routers for home users

RV130W Wireless-N Multifunction VPN Router
Hardware solutions / Routers for home users

Cisco Small Business RV130 Series VPN Routers
Hardware solutions / Routers for home users

RV215W Wireless-N VPN Router
Hardware solutions / Routers for home users

Vendor Cisco Systems, Inc

Security Bulletin

This security bulletin contains one critical risk vulnerability.

1) Stack-based buffer overflow

EUVDB-ID: #VU56020

Risk: Critical

CVSSv3.1: 9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:U/RC:C]

CVE-ID: CVE-2021-34730

CWE-ID: CWE-121 - Stack-based buffer overflow

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in the Universal Plug-and-Play (UPnP) service. A remote unauthenticated attacker can send a specially crafted UPnP request to an affected device, trigger stack-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Cisco is not planning to release any security updates for the affected devices, as they have reached the end-of-life status.

As a workaround it is recommended to disable UPnP.

To disable UPnP on the LAN interface of a device, do the following:

  1. Open the web-based management interface and choose Basic Settings > UPnP.
  2. Check the Disable check box.

Vulnerable software versions

RV110W Wireless-N VPN Firewall: 1.0.0.2 - 1.3.1.7

RV130W Wireless-N Multifunction VPN Router: 1.0.0.21 - 1.3.1.7

Cisco Small Business RV130 Series VPN Routers: 1.0.0.21 - 1.3.1.7

RV215W Wireless-N VPN Router: 1.0.3.55 - 1.3.1.7

External links

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cisco-sb-rv-overflow-htpymMB5
http://bst.cloudapps.cisco.com/bugsearch/bug/CSCvz05607


Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected device in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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



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