CVE-2017-18785

Vulnerability

A cross-site scripting (XSS) vulnerability exists in the web-based management interface of numerous NETGEAR routers, gateways, and extender models. The flaw can be triggered when the device processes unsanitized input, allowing an attacker to inject malicious scripts [1]. Affected firmware versions include D3600 before 1.0.0.67, D6000 before 1.0.0.67, D6100 before 1.0.0.56, D6200 before 1.1.00.24, D6220 before 1.0.0.32, D6400 before 1.0.0.66, D7000 before 1.0.1.52, D7000v2 before 1.0.0.44, D7800 before 1.0.1.30, D8500 before 1.0.3.35, DGN2200v4 before 1.0.0.96, DGN2200Bv4 before 1.0.0.96, EX2700 before 1.0.1.28, EX6100v2 before 1.0.1.54, EX6150v2 before 1.0.1.54, EX6200v2 before 1.0.1.52, EX6400 before 1.0.1.72, EX7300 before 1.0.1.72, EX8000 before 1.0.0.102, JNR1010v2 before 1.1.0.44, JWNR2010v5 before 1.1.0.44, PR2000 before 1.0.0.20, R6020 before 1.0.0.26, R6080 before 1.0.0.26, R6100 before 1.0.1.20, R6250 before 1.0.4.16, R6300v2 before 1.0.4.18, R6400 before 1.0.1.32, R6400v2 before 1.0.2.46, R6700 before 1.0.1.36, R6800 before 1.2.0.12, R6900v2 before 1.2.0.12, R6700v2 before 1.2.0.12, R6900 before 1.0.1.34, R6900P before 1.3.0.8, R7000 before 1.0.9.18, R7000P before 1.3.0.8, R7100LG before 1.0.0.34, R7300DST before 1.0.0.58, R7500 before 1.0.0.118, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R7900 before 1.0.2.4, R7900P before 1.1.5.14, R8000 before 1.0.4.4, R8000P before 1.1.5.14, R8500 before 1.0.2.110, R8300 before 1.0.2.110, R9000 before 1.0.2.52, WN2000RPTv3 before 1.0.1.8, WN3000RPv3 before 1.0.2.50, WN3100RPv2 before 1.0.0.42, WNDR3400v3 before 1.0.1.16, WNDR3700v4 before 1.0.2.94, WNDR4300 before 1.0.2.96, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, WNR1000v4 before 1.1.0.44, WNR2000v5 before 1.0.0.62, WNR2020 before 1.1.0.44, WNR2050 before 1.1.0.44, and WNR3500Lv2 before 1.2.0.46 [1].

Exploitation

To exploit the vulnerability, an attacker must craft a malicious request containing injected JavaScript in a parameter that is not properly sanitized by the device's web interface. The attacker then needs to convince a logged-in administrator to access the crafted link (e.g., via email or another web page) or to navigate to a page that reflects the injected script. No authentication is required to deliver the encoded payload, but the successful execution depends on an authenticated session being active when the payload is rendered [1].

Impact

Successful exploitation allows the attacker to execute arbitrary JavaScript within the context of the authenticated administrator's browser session. This can lead to theft of session cookies, modification of device configuration, extraction of sensitive network information, or redirection to malicious sites. The scope of compromise is limited to the web interface session, but an attacker could leverage the access to perform privileged actions on the affected device [1].

Mitigation

NETGEAR has released firmware updates that address the XSS vulnerability. Users should upgrade to the fixed versions listed for each model (or later releases) as provided in the advisory [1]. At the time of publication, no workaround is available other than applying the firmware update. The vulnerability is not known to be listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.