CVE-2020-25856 Explained : Impact and Mitigation

Realtek RTL8195A Wi-Fi Module prior to versions released in April 2020 (up to and excluding 2.08) is vulnerable to a stack buffer overflow, allowing for remote code execution or denial of service.

Understanding CVE-2020-25856

This CVE identifies a critical vulnerability in the Realtek RTL8195A Wi-Fi Module that can be exploited by attackers for malicious purposes.

What is CVE-2020-25856?

The vulnerability in the Realtek RTL8195A Wi-Fi Module allows attackers to trigger a stack buffer overflow through a specific function, potentially leading to remote code execution or denial of service attacks.

The Impact of CVE-2020-25856

Exploiting this vulnerability enables attackers to impersonate an Access Point and target vulnerable Wi-Fi clients by injecting crafted packets into the WPA2 handshake. Knowledge of the network's PSK is required for successful exploitation.

Technical Details of CVE-2020-25856

The technical aspects of the CVE-2020-25856 vulnerability provide insight into its nature and potential risks.

Vulnerability Description

The vulnerability arises from the lack of validation for the size parameter in the DecWPA2KeyData() function, leading to a stack buffer overflow during an rtl_memcpy() operation.

Affected Systems and Versions

Product: Realtek RTL8195A Wi-Fi Module
Versions Affected: Before 2020-04-21 (up to and excluding 2.08)

Exploitation Mechanism

The vulnerability can be exploited by injecting a crafted packet into the WPA2 handshake, allowing attackers to execute remote code or launch denial of service attacks.

Mitigation and Prevention

Protecting systems from CVE-2020-25856 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply security patches provided by Realtek for the affected versions.
Monitor network traffic for any suspicious activities related to WPA2 handshakes.

Long-Term Security Practices

Regularly update Wi-Fi module firmware to the latest versions.
Implement network segmentation to isolate critical devices from potential attacks.

Patching and Updates

Realtek has released patches addressing the vulnerability; ensure timely installation to mitigate the risk of exploitation.