CVE-2018-3953

2018-10-1600:00:00

talos

www.cve.org

7.2 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

7.4 High

AI Score

Confidence

High

0.002 Low

EPSS

Percentile

57.8%

JSON

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.

CNA Affected

[
  {
    "product": "ESeries E1200",
    "vendor": "Linksys",
    "versions": [
      {
        "status": "affected",
        "version": "Firmware Version 2.0.09"
      }
    ]
  },
  {
    "product": "ESeries E2500",
    "vendor": "Linksys",
    "versions": [
      {
        "status": "affected",
        "version": "Firmware Version 3.0.04"
      }
    ]
  }
]