CVE-2017-18737
Executive Summary
CVE-2017-18737 is a command injection vulnerability affecting a broad range of Netgear consumer and small-business routers, including the JNR1010v2, JR6150, JWNR2010v5, PR2000, R6050, R6220, R6700v2, R6800, R6900v2, WNDR3700v5, WNR1000v4, WNR2020, and WNR2050 models. The vulnerability is exploitable by an unauthenticated remote attacker, allowing arbitrary command execution on the underlying operating system of affected devices. Successful exploitation grants full control of the router, enabling traffic interception, network pivoting, and persistent compromise.
The vulnerability carries a CVSS score of 8.8, indicating high severity, and has an EPSS score of 0.01836 (76.9th percentile), suggesting moderate real-world exploitation likelihood. No public proof-of-concept, Nuclei template, or exploit code has been identified. Crucially, patch confidence is rated 0/4 — no authoritative patch evidence has been gathered from any tracked source, placing affected devices at sustained risk.
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Technical Analysis
The NVD description indicates that certain Netgear devices are affected by a command injection vulnerability exploitable by an unauthenticated attacker. Command injection (CWE-77) occurs when user-controlled input is incorporated into a command executed by the operating system without adequate sanitization or escaping.
The attack surface is the router's web-based management interface or other network-exposed services that accept HTTP requests. The vulnerability class suggests that specific parameters within HTTP requests are concatenated into system-level commands — such as shell commands invoked via functions like popen(), system(), or equivalent — without proper input validation. An attacker crafts a payload that includes command separators (e.g., ;, &&, |) or command substitution syntax to inject an arbitrary OS command alongside the intended legitimate command.
No specific function names, URL endpoints, or parameter identifiers are provided in the NVD description, and the CNA Title field is empty. Consequently, the precise implementation details of the vulnerability — such as which HTTP parameter triggers the injection or which underlying command is being constructed — remain unavailable from the supplied data. The absence of technical detail precludes a code-level analysis; the vulnerability must be understood at the class level.
Affected firmware versions span multiple product lines, indicating a recurring pattern of insecure command construction that likely shares root cause across these models. The affected devices are primarily home and small-office routers, which are typically deployed at the network perimeter and expose their management interfaces to LAN clients, and in some configurations, to the WAN side, significantly broadening the remote attack surface.
Exploitation Scenarios
No public PoC is available; the attack chain is inferred from the vulnerability class (command injection) and the devices' typical deployment posture.
Step 1 — Reconnaissance/Target Identification: An attacker first identifies vulnerable Netgear devices. This is commonly accomplished via internet-wide scanning for open ports associated with Netgear router management interfaces (typically TCP 80, 8080, or 443) using tools such as Shodan, Censys, or masscan. Accessible device fingerprints — HTTP banners, login pages, or model identifiers — confirm the presence of a vulnerable model and firmware version.
Step 2 — Triggering the Flaw: The attacker sends a crafted HTTP request to the management interface. The request includes a specially crafted value in an input parameter that the device's web server processes. Because the application fails to sanitize the input, special shell metacharacters (e.g., ;, $(...), backticks) within the value cause the device to execute an unintended operating system command when the original command is run.
Step 3 — Payload/Execution: At the vulnerability-class level, the attacker constructs a payload that first completes the intended command and then appends a malicious command. An example payload at the conceptual level would append ; command to a legitimate input string, where command is a system command such as wget or curl to download malware, or reboot to cause denial-of-service. Since the injection occurs in a shell context without authentication, the injected command executes with whatever privileges the web service runs under — typically root on embedded router firmware.
Step 4 — Post-Exploitation Impact: Successful exploitation grants the attacker command execution with elevated (typically root) privileges. The attacker can then:
- Exfiltrate sensitive data (credentials, Wi-Fi passwords, VPN keys).
- Modify router firmware or configuration (e.g., DNS settings to redirect traffic to malicious servers).
- Install persistent backdoors or botnet agents.
- Pivot into the internal network by using the router as a foothold to target connected LAN hosts.
- Disable logging or security measures to evade detection.
The attack requires no authentication and no user interaction, making it particularly dangerous on devices exposed to the internet.
Impact Assessment
The CVSS score of 8.8 is classified as High severity. The inferred CVSS vector reflects a network-exploitable (AV:N), low-complexity (AC:L) attack requiring no privileges (PR:N) and no user interaction (UI:N). The scope is unchanged (S:U), with high confidentiality, integrity, and availability impact (C:H/I:H/A:H).
Business Impact: As consumer/small-business gateways, these devices control network egress and ingress. Full compromise of even one device exposes the organization's internal network to lateral movement, data theft, and further compromise. For enterprises that deploy these devices in remote offices or as part of managed service infrastructure, the impact is amplified — a compromised router can intercept all branch-office traffic.
Affected Systems: Thirteen product models spanning multiple firmware branches, including:
- JNR1010v2 (fixed in 1.1.0.44)
- JR6150 (fixed in 1.0.1.10)
- JWNR2010v5 (fixed in 1.1.0.44)
- PR2000 (fixed in 1.0.0.18)
- R6050 (fixed in 1.0.1.10)
- R6220 (fixed in 1.1.0.50)
- R6700v2, R6800, R6900v2 (fixed in 1.2.0.4)
- WNDR3700v5 (fixed in 1.1.0.48)
- WNR1000v4, WNR2020, WNR2050 (fixed in 1.1.0.44)
Blast Radius: Any affected device still on an older firmware version is vulnerable. Given that embedded devices often remain unpatched for years, the installed base at risk is likely substantial. The lack of confirmed patch availability (patch confidence 0/4) compounds the risk, as even patching may not be feasible for all models.
Detection Guidance
The detection signatures below target network-level and host-level indicators consistent with command-injection attempts against Netgear router interfaces. Since no specific endpoint or parameter is known, the rules focus on detection of shell metacharacters in HTTP requests to common router management paths, on anomalous outbound connections from router devices, and on unexpected process executions on the router host.
Sigma Rule
title: Netgear Router Command Injection Attempt (CVE-2017-18737)
id: 459e2b18-2b4e-4f6a-9c4c-d1f0a3b7c5e9
status: experimental
description: Detects HTTP requests containing shell metacharacters sent to Netgear router management interfaces, potentially indicating exploitation of CVE-2017-18737 command injection.
references:
- https://nvd.nist.gov/vuln/detail/CVE-2017-18737
author: Valtersit Threat Intel
date: 2025/01/18
tags:
- attack.initial-access
- attack.t1190
logsource:
category: webserver
product: proxy
detection:
selection:
http.url_path|contains:
- '/cgi-bin/'
- '/setup.cgi'
- '/goform/'
http.url_query|contains:
- ';'
- '|'
- '`'
- '$(('
- '&&'
- '> /dev/null'
filter:
http.user_agent|contains:
- 'Mozilla' # exclude normal browsers
- 'curl'
- 'wget'
condition: selection and not filter
level: high
falsepositives:
- Legitimate administrative commands containing semicolons in URL parameters (rare)
- URL-encoded payloads that are decoded after detection point
fields:
- src_ip
- dest_ip
- http.url_path
- http.url_query
YARA Rule
rule netgear_cve_2017_18737_command_injection_payloads {
meta:
author = "Valtersit Threat Intel"
description = "Detect shell command injection payloads targeting Netgear routers"
reference = "CVE-2017-18737"
date = "2025-01-18"
score = 70
strings:
$s1 = /(?:;|&&|\|\|)\s*(?:cat|wget|curl|nc|ncat|telnet|sh|bash|cmd|reboot|poweroff|halt|ls|cd|echo)\b/ nocase
$s2 = /\$\((?:cat|wget|curl|nc|ls|sh|bash)\s/ nocase
$s3 = /`(?:cat|wget|curl|nc|ls|sh|bash)\s/ nocase
$s4 = "cgi-bin" ascii
$s5 = "goform" ascii
condition:
any of ($s1, $s2, $s3) and (any of ($s4, $s5) or filesize < 250KB)
}
Suricata IDS Rule
alert http any any -> $HOME_NET any (msg:"ET EXPLOIT Netgear Router Command Injection Attempt (CVE-2017-18737)"; flow:established,to_server; content:"cgi-bin"; http_uri; nocase; pcre:"/[\x3b\x7c\x60\x24]/Ui"; http_uri; pcre:"/(?:cat|wget|curl|nc|sh|bash|reboot|ls|echo)\b/Ui"; http_uri; classtype:attempted-admin; sid:2027001; rev:1; metadata:created_at 2025_01_18, updated_at 2025_01_18;)
Elastic Detection
sequence by source.ip
[ network where event.category == "network_traffic" and destination.port in (80, 443, 8080) and
url.path like "*cgi-bin*" and (
url.query contains ";" or url.query contains "|" or url.query contains "`" or
url.query contains "$((" or url.query contains "&&"
)
]
[ process where event.category == "process" and event.action == "exec" and
process.command_line regex~ ".*(cat|wget|curl|nc|sh|bash|reboot|ls|echo).*"
]
Splunk SPL Query
index=web OR index=proxy
| where match(_raw, "(?i)(cgi-bin|goform)")
| where match(_raw, "[;|`$]")
| where match(_raw, "(?i)(cat|wget|curl|nc|ncat|sh|bash|reboot|ls|echo)")
| stats count by src_ip, dest_ip, http_url, _time
| sort - _time
| table _time, src_ip, dest_ip, http_url, count
Wazuh OSSEC Rule
<rule id="100257" level="12">
<decoded_as>web</decoded_as>
<description>Netgear Router Command Injection Attempt (CVE-2017-18737)</description>
<group>webserver,attack,t1190,</group>
<regex>cgi-bin|goform</regex>
<regex>[;|`$]</regex>
<regex>(?i)(cat|wget|curl|nc|sh|bash|reboot|ls|echo)</regex>
<mitre>
<id>T1190</id>
</mitre>
</rule>
Mitigation & Patch Guidance
Patch Confidence: 0/4 — UNPATCHED. No patch evidence has been found in any tracked source. Although the NVD description lists "fixed" firmware versions, no advisory, changelog, or vendor download link confirming availability of these versions has been verified. Proceed with caution and assume devices remain vulnerable until proven otherwise.
Immediate Mitigations (to deploy right now):
- Disable remote management: Ensure WAN-side management of the device is disabled in firmware settings. Restrict management interface access to trusted LAN IPs only, where possible.
- Network segmentation: Isolate affected Netgear devices behind a dedicated firewall or VLAN that restricts inbound HTTP/S traffic to management ports.
- Firewall filtering: Deploy perimeter firewall rules to block access to the management web interface (typically TCP 80, 443, 8080) from external sources.
- Monitor and alert: Enable logging on the router and network perimeter, and feed the detection rules above into SIEM/log aggregation.
Patch/Upgrade Steps:
5. Check Netgear's official support/download portal for each specific model listed in the description and obtain the indicated fixed firmware version (e.g., 1.1.0.44 for JNR1010v2, 1.2.0.4 for R6700v2).
6. Verify the firmware checksum/hash published by Netgear before installation to prevent tampering.
7. Apply the firmware update via the router's web interface or CLI, following vendor instructions.
8. After upgrading, verify the firmware version via the router's status page.
Long-Term Hardening: 9. Replace end-of-life or unsupported devices that no longer receive firmware updates with supported, actively-maintained hardware. 10. Implement a firmware/patch management program to track network device versions and schedule regular update checks. 11. Use strong administrator credentials for all network devices; change default passwords immediately. 12. Disable unused services (UPnP, IPv6 if not needed, remote syslog, SNMP) to reduce the attack surface. 13. Consider 802.1X or other network-level access controls to reduce the likelihood of LAN-side attack.
References
- NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2017-18737
- Netgear Security Advisory Index (search by CVE): https://kb.netgear.com/en-US/security
- CISA Known Exploited Vulnerabilities Catalog (no KEV entry as of report date): https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Shodan search for exposed Netgear devices: https://www.shodan.io/search?query=Netgear+router
- EPSS Data (FIRST.org): https://www.first.org/epss/
Known Threat Actor Campaigns / Exploit-in-the-Wild: No evidence of active exploitation in the wild has been identified for CVE-2017-18737 specifically. No CISA KEV entry exists, and no threat-actor campaigns referencing this exact CVE were found in tracked sources. However, Netgear routers broadly are frequent targets of botnet operators (e.g., Mirai-related) and APT groups seeking initial access; the command-injection class is a favoured target. Monitor Netgear advisories and CERT notifications for updates, as patch confirmation and additional exploit details may emerge.
Report generated by Valtersit Threat Intelligence. This document is based on information available as of the report date and may not include subsequent developments. Always verify with primary sources before acting.
What is this? Security researchers use these exact search queries on Shodan.io (a search engine for internet-connected devices) to find vulnerable systems globally. You can copy these dorks to see if your organization's IP space is exposed.