Multiple Vulnerabilities in SonicWALL Sonic OS Could Allow for Arbitrary Code Execution

ITS ADVISORY NUMBER: 

2020-141

DATE(S) ISSUED: 

Friday, October 16, 2020

SUBJECT: 

Multiple Vulnerabilities in SonicWALL Sonic OS Could Allow for Arbitrary Code Execution

OVERVIEW: 

Multiple vulnerabilities have been discovered in SonicWALL Sonic OS, the most severe of which could allow for arbitrary code execution. SonicWALL is a firewall and cybersecurity solution vendor. Successful exploitation of the most severe of these vulnerabilities could allow for buffer overflow within the context of the application. Attackers may exploit this issue to execute arbitrary code within the context of the affected application. Failed exploits may result in denial-of-service conditions.

THREAT INTELLIGENCE:

There are currently no reports of these vulnerabilities being exploited in the wild.

SYSTEMS AFFECTED: 

  • SonicOS 6.5.4.7-79n and earlier

  • SonicOS 5.9.1.7-2n and earlier

  • SonicOS 5.9.1.13-5n and earlier

  • SonicOS 6.5.1.11-4n and earlier

  • SonicOS 6.0.5.3-93o and earlier

  • SonicOSv 6.5.4.4-44v-21-794 and earlier

  • SonicOS 7.0.0.0-1

RISK:

Government:

Large and medium government entities: High

Small government entities: High

Business:

Large and medium business entities: High

Small business entities: High

Home Users: Low

 

DESCRIPTION: 

Multiple vulnerabilities have been discovered in SonicWALL Sonic OS, the most severe of which could allow for arbitrary code execution. Successful exploitation of the most severe of these vulnerabilities could allow for buffer overflow within the context of the application. Details of these vulnerabilities are as follows: 

  • SonicWALL Sonic OS is prone to a stack-based buffer-overflow vulnerability because it fails to properly bounds-check user-supplied data before copying it into an insufficiently sized buffer. An attacker can exploit this issue by sending a specially-crafted 'HTTP' request containing a custom protocol handler to the affected device. [CVE-2020-5135]

  • A heap-based buffer-overflow vulnerability that affects the firewall SSLVPN service. A remote unauthenticated attacker can exploit this issue to crash the Sonic OS denying service to the legitimate users. [CVE-2020-5138]

  • A buffer-overflow vulnerability that affects the firewall SSLVPN service. A remote unauthenticated attacker can exploit this issue to crash the firewall denying service to the legitimate users. [CVE-2020-5137] 

Attackers may exploit this issue to execute arbitrary code within the context of the affected application. Failed exploits may result in denial-of-service conditions.

ACTIONS: 

  • After appropriate testing, immediately apply patches provided SonicWALL to vulnerable systems.

  • Disable all unnecessary services.

  • Restrict access to devices and applications from only authorized users and hosts.

  • Remind users not to visit websites or follow links provided by unknown or untrusted sources.

  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments especially from un-trusted sources.

  • Apply the Principle of Least Privilege to all systems and services.

REFERENCES: 

SonicWALL:
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2020-0012
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2020-0013
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2020-0010

CVE:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-5138
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-5137
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-5135