HIGH

CVE-2018-3953

CVSS v3

7.2

HIGH

EPSS Score

68.5%

exploit probability

CISA KEV

No

known exploited

Exploitation

SSVC status

Description

Devices in the Linksys ESeries line of routers (Linksys E1200 Firmware Version 2.0.09 and Linksys E2500 Firmware Version 3.0.04) are susceptible to OS command injection vulnerabilities due to improper filtering of data passed to and retrieved from NVRAM. Data entered into the 'Router Name' input field through the web portal is submitted to apply.cgi as the value to the 'machine_name' POST parameter. When the 'preinit' binary receives the SIGHUP signal, it enters a code path that continues until it reaches offset 0x0042B5C4 in the 'start_lltd' function. Within the 'start_lltd' function, a 'nvram_get' call is used to obtain the value of the user-controlled 'machine_name' NVRAM entry. This value is then entered directly into a command intended to write the host name to a file and subsequently executed.

Technical details

Published
10/17/2018

Frequently asked questions

What is CVE-2018-3953?

Devices in the Linksys ESeries line of routers (Linksys E1200 Firmware Version 2.0.09 and Linksys E2500 Firmware Version 3.0.04) are susceptible to OS command injection vulnerabilities due to improper filtering of data passed to and retrieved from NVRAM. Data entered into the 'Router Name' input field through the web portal is submitted to apply.cgi as the value to the 'machine_name' POST parameter. When the 'preinit' binary receives the SIGHUP signal, it enters a code path that continues until it reaches offset 0x0042B5C4 in the 'start_lltd' function. Within the 'start_lltd' function, a 'nvram_get' call is used to obtain the value of the user-controlled 'machine_name' NVRAM entry. This value is then entered directly into a command intended to write the host name to a file and subsequently executed.

Is CVE-2018-3953 actively exploited?

Active exploitation of CVE-2018-3953 has not been confirmed. The EPSS score is 68.5%, indicating the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-3953?

CVE-2018-3953 has a CVSS v3 base score of 7.2 (HIGH severity).

Is CVE-2018-3953 affecting your environment?

Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.