CVE-2020-11881 Explained : Impact and Mitigation

An array index error in MikroTik RouterOS 6.41.3 through 6.46.5, and 7.x through 7.0 Beta5, allows an unauthenticated remote attacker to crash the SMB server via modified setup-request packets, aka SUP-12964.

Understanding CVE-2020-11881

This CVE identifies a vulnerability in MikroTik RouterOS that can be exploited by an unauthenticated remote attacker to disrupt the SMB server.

What is CVE-2020-11881?

The vulnerability in MikroTik RouterOS versions 6.41.3 through 6.46.5, and 7.x through 7.0 Beta5, enables a remote attacker to crash the SMB server using altered setup-request packets.

The Impact of CVE-2020-11881

The exploitation of this vulnerability can lead to a denial of service (DoS) condition on the affected SMB server, potentially disrupting network services and operations.

Technical Details of CVE-2020-11881

This section provides more in-depth technical insights into the CVE.

Vulnerability Description

The vulnerability arises from an array index error in MikroTik RouterOS, allowing unauthorized users to send manipulated setup-request packets, resulting in a crash of the SMB server.

Affected Systems and Versions

MikroTik RouterOS versions 6.41.3 through 6.46.5
MikroTik RouterOS versions 7.x through 7.0 Beta5

Exploitation Mechanism

The vulnerability can be exploited remotely by sending specially crafted setup-request packets to the targeted SMB server, triggering the array index error and causing the server to crash.

Mitigation and Prevention

Protecting systems from CVE-2020-11881 requires immediate actions and long-term security measures.

Immediate Steps to Take

Apply vendor-supplied patches or updates to mitigate the vulnerability promptly.
Implement network segmentation to limit the impact of potential attacks on the SMB server.

Long-Term Security Practices

Regularly monitor and update network security configurations to prevent similar vulnerabilities.
Conduct security assessments and penetration testing to identify and address potential weaknesses in the network infrastructure.

Patching and Updates

Stay informed about security advisories from MikroTik and apply patches as soon as they are released to ensure system protection.