The new ASUS router firmware update contains security patches for nine vulnerabilities amongst other important security fixes. Six of these vulnerabilities are high severity flaws, while another two, from 2018 and 2022, are rated as critical, with CVSS base scores of 9.8. Four of the high severity flaws were also legacy fixes from 2022, while the remaining three flaws patched were newer vulnerabilities published this month. One of these three flaws tracked as CVE-2023-31195 is yet to receive a severity rating and CVSS base score due to it only being added to NIST’s National Vulnerability Database last week. This flaw found in RT-AX3000 routers causes sensitive cookies to be used without the Secure attribute. An attacker can exploit this to perform a man-in-the-middle attack when a user logs in using an unencrypted HTTP connection by stealing the authentication cookies and hijacking the session.  

The other two vulnerabilities published this month that were patched in this recent update both affect ASUS RT-AC86U devices. The first flaw tracked as CVE-2023-28702 is a high severity flaw with a CVSS base score of 8.8. This vulnerability causes the router to mishandle special characters by not filtering for parameters in some specific web URLs. An attacker with basic user privileges can exploit this command injection flaw remotely in order to execute commands, disrupt, or terminate the system. The other high severity flaw for this device is tracked as CVE-2023-28703 has been assigned a CVSS base score of 7.1 This vulnerability is due to insufficient validation of the network packet header length, causing a stack-based buffer overflow in the cgi function of vulnerable devices. To exploit this an attacker first needs to obtain administrator privileges, however they can then remotely access the system to execute commands, disrupt, or terminate the system.  

The first critical severity flaw addressed in this update is CVE-2018-1160, an out of bounds write vulnerability. This vulnerability affects Netatalk, an open-source fileserver, where there is an issue with bounds checking. This allows a remote unauthenticated attacker to perform code execution in the dsi_opensess.c file. The other critical severity flaw patched is CVE-2022-26376, a memory corruption vulnerability found in Asuswrt firmware. This flaw is present in the httpd unescape functionality of Asuswrt versions before 3.0.0.4.386_48706 and Asuswrt-Merlin New Gen versions before 386.7. To exploit this vulnerability an attacker can craft and send a malicious HTTP request to the vulnerable network in order to trigger memory corruption.   

In a security advisory published this week ASUS confirm this firmware update is for router models GT6, GT-AXE16000, GT-AX11000 PRO, GT-AXE11000, GT-AX6000, GT-AX11000, GS-AX5400, GS-AX3000, ZenWiFi XT9, ZenWiFi XT8, ZenWiFi XT8 V2, RT-AX86U PRO, RT-AX86U, RT-AX86S, RT-AX82U, RT-AX58U, RT-AX3000, TUF-AX6000, and TUF-AX5400. To apply the latest firmware updates users can visit the Support page of the ASUS site or the specific product page to find download links. Users of any of these devices are also “strongly encouraged” by ASUS to periodically audit their equipment and security practices in order to be best protected.