Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
High
Attack Vector
Network
0

CVE-2018-3953

Disclosure Date: October 17, 2018
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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.

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CVSS V3 Severity and Metrics
Base Score:
7.2 High
Impact Score:
5.9
Exploitability Score:
1.2
Vector:
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
High
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Additional Info

Technical Analysis