CVE-2017-2873

Executive Summary

CVE-2017-2873 identifies an exploitable command injection vulnerability in the web management interface of the Foscam C1 Indoor HD Camera running application firmware version 2.52.2.43. A remote attacker can send a specially crafted HTTP request that injects arbitrary shell characters during the SoftAP configuration process, resulting in arbitrary command execution on the device with the privileges of the underlying system process. Given the network-exposed nature of the device and the high CVSS score of 8.8, this represents a serious risk requiring immediate segmentation and monitoring for affected devices.

Technical Analysis

The vulnerability resides in the SoftAP configuration functionality exposed through the web management interface of the Foscam C1 Indoor HD Camera. The SoftAP (Software Access Point) feature allows the camera to create its own Wi-Fi network for initial setup and configuration purposes. During this configuration process, user-supplied input is passed to a system shell without sufficient sanitization or escaping of shell metacharacters.

The core issue is a classic OS command injection vulnerability class (CWE-78: Improper Neutralization of Special Elements used in an OS Command). When an HTTP request containing malicious shell characters (such as semicolons, pipes, dollar signs, or command substitution operators) is sent to the SoftAP configuration endpoint, the embedded web server concatenates this input into a command string that is subsequently executed by the operating system shell.

According to the NVD description, "A specially crafted HTTP request can allow for a user to inject arbitrary shell characters during the SoftAP configuration resulting in command injection. An attacker can simply send an HTTP request to the device to trigger this vulnerability." The phrase "simply send an HTTP request" indicates that no authentication bypass or complex multi-step exploitation is required — the attack surface is the standard HTTP management interface, which is internally accessible over the network.

The web management interface is the primary administrative surface for the camera, typically listening on TCP port 80 (HTTP) and potentially other ports depending on configuration. The attack does not require authentication details to be known in advance, though whether authentication is required to access the vulnerable parameter is not specified in the provided data. Given the CVSS vector of AV:N (network) with AC:L (low attack complexity) and the score of 8.8, the attack is remotely exploitable without requiring physical access.

Insufficient technical detail is available to specify the exact URL endpoint, parameter name, or shell command construction method. The vulnerability exists specifically in the SoftAP configuration logic of firmware 2.52.2.43, and exploitation results in arbitrary shell command execution with the privileges of the web server process — typically root on embedded camera firmware such as this, given the single-purpose nature of the devices.

Exploitation Scenarios

1. Reconnaissance and Target Identification

An attacker identifies Foscam C1 Indoor HD Camera devices through network scanning. Shodan and other IoT search engines index devices exposing the web management interface. The device's default HTTP management page typically reveals the Foscam branding and camera model. Attackers may also use banner grabbing or port scanning (TCP 80, 443, 8080) to identify candidate targets. Since the NVD description does not specify authentication requirements, the attacker may target both unauthenticated devices and devices with default credentials.

2. Triggering the Vulnerability

The attacker sends a crafted HTTP request to the web management interface, specifically targeting the SoftAP configuration functionality. The request contains shell metacharacter sequences within the configuration parameters. Because the vulnerable code path does not sanitize input, the injection payload is interpreted by the underlying OS shell. The attack vector is exclusively the HTTP management interface — no other protocol or service is implicated per the description.

No public PoC is available; the attack chain at the request-format level is inferred from the vulnerability class (command injection) and the SoftAP configuration context.

3. Payload Execution Method

At the vulnerability-class level, the attacker embeds command separator characters (e.g., ;, &&, |, backticks) or command substitution syntax within the SoftAP configuration fields. The web server constructs a shell command that includes the user-supplied values and executes it via a system shell invocation. The injected payload executes with the same privileges as the web server process. Given typical IoT camera firmware architecture, this is frequently root-level access. Example payload structure at the conceptual level: legitimate configuration value followed by command separator, followed by arbitrary attacker command.

The payload would commonly include commands to:

• Extract sensitive data (e.g., /etc/passwd, Wi-Fi credentials stored in device configuration)
• Establish persistence (e.g., download and execute a botnet binary or malware payload)
• Pivot laterally into the local network
• Disable logging or modify device firmware settings

4. Post-Exploitation Impact

Successful exploitation grants the attacker arbitrary shell access to the camera's underlying operating system. Post-exploitation objectives typically include:

• Data theft: Camera streams and stored footage accessible via filesystem access
• Botnet recruitment: The camera joins IoT botnets (e.g., Mirai family) due to its always-on network connectivity and limited security controls
• Network pivot: The compromised camera becomes a foothold for lateral movement into the home or office LAN
• Privacy invasion: Real-time video/audio surveillance compromise
• Device destruction: Command execution permits complete device firmware wipe or bricking

Impact Assessment

CVSS Analysis: The CVSS score of 8.8 (High) is justified. The broad vector components — network-based exploitation, low complexity, no special privilege requirements, and high confidentiality/integrity/availability impact — indicate that any exposed device can be trivially compromised with significant downstream consequences.

Affected Systems: All Foscam C1 Indoor HD Camera units running application firmware 2.52.2.43. The affected version list provided is empty, meaning the full scope of affected firmware versions is unknown; the NVD description specifically references 2.52.2.43, and other versions may be vulnerable.

Blast Radius:

• Device-level: Full administrative control of the camera
• Network-level: Access to the LAN segment where the camera resides
• Data-level: Exposure of video feeds, audio recordings, Wi-Fi credentials, and device configuration
• Compliance-level: For enterprise environments, unapproved IoT devices on corporate networks represent a compliance violation and a data exfiltration vector

Business Impact: For home users, privacy invasion and security risks. For enterprise environments (retail stores, warehouses, offices) using unauthorized IoT cameras, this vulnerability exposes facility monitoring data, can be used for surveillance sabotage, or serve as an entry point into the broader network. The EPSS score of 0.05040 (91.5th percentile) indicates that this vulnerability is in the upper percentile of likelihood-of-exploitation scores among known CVEs, suggesting active scanning and exploitation attempts in the wild with high probability.

Detection Guidance

Sigma Rule

title: Foscam C1 SoftAP Command Injection Attempt
id: fc1e7a2b-9f34-4f5a-8c2d-6b3a8f91c2d4
status: experimental
description: Detects HTTP requests to Foscam C1 cameras attempting command injection via SoftAP configuration parameters
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2017-2873
author: Valtersit Threat Intelligence
date: 2024/06/01
logsource:
    category: webserver
    product: generic
detection:
    selection_foscam:
        cs-method: 'GET'
        cs-host|contains: 
            - 'foscam'
            - '192.168.'
            - '10.'
    selection_injection_chars:
        cs-uri-query|contains:
            - ';'
            - '|'
            - '&&'
            - '`'
            - '$(('
            - '`id`'
            - '%3B'
            - '%26%26'
            - '%7C'
            - 'reboot'
            - 'wget'
            - 'curl'
            - 'tftp'
    condition: selection_foscam and selection_injection_chars
falsepositives:
    - Legitimate configuration changes containing semicolons (unlikely in normal operation)
level: high

YARA Rule

rule Foscam_C1_SoftAP_Command_Injection
{
    meta:
        author = "Valtersit Threat Intelligence"
        description = "Detects HTTP payloads targeting Foscam C1 SoftAP configuration with command injection characters"
        reference = "CVE-2017-2873"
        date = "2024-06-01"
        score = 80
    
    strings:
        $softap_ref = "softap" ascii nocase
        $ap_ref = "ap_config" ascii nocase
        $shell_seps = ";" ascii
        $shell_pipe = "|" ascii
        $shell_and = "&&" ascii
        $shell_backtick = "`" ascii
        $shell_subst = "$(" ascii
        $cmd_common = "reboot" ascii nocase
        $cmd_wget = "wget" ascii nocase
        $cmd_curl = "curl" ascii nocase

    condition:
        ($softap_ref or $ap_ref) and 2 of ($shell_seps, $shell_pipe, $shell_and, $shell_backtick, $shell_subst) and 1 of ($cmd_common, $cmd_wget, $cmd_curl)
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2017-2873 Foscam C1 SoftAP Command Injection Attempt"; flow:to_server,established; content:"softap"; http_uri; nocase; content:";"; http_uri; distance:0; content:"|"; http_uri; distance:0; content:"&&"; http_uri; distance:0; content:"`"; http_uri; distance:0; content:"$("; http_uri; distance:0; classtype:attempted-admin; reference:cve,2017-2873; sid:1002873; rev:1;)

Elastic Detection

network where event.type == "connection" and network.protocol == "http"
  and process.name == "httpd" or process.name == "lighttpd" or process.name == "boa"
  and url.path contains "softap" or url.query contains "softap"
  and (
    url.query contains ";" or
    url.query contains "|" or
    url.query contains "&&" or
    url.query contains "`" or
    url.query contains "$(" or
    url.query contains "%3B" or
    url.query contains "%7C" or
    url.query contains "%26%26"
  )

Splunk SPL Query

index=web sourcetype=access_combined
| search (uri_path="*softap*" OR uri_query="*softap*")
| search (
    uri_query="*;*" OR
    uri_query="*|*" OR
    uri_query="*&&*" OR
    uri_query="*`*" OR
    uri_query="*$(*" OR
    uri_query="*%3B*" OR
    uri_query="*%7C*" OR
    uri_query="*%26%26*"
)
| search (uri_query="*reboot*" OR uri_query="*wget*" OR uri_query="*curl*" OR uri_query="*tftp*")
| table _time, src_ip, dest_ip, uri_path, uri_query, http_method
| sort - _time

Wazuh OSSEC Rule

<group name="foscam,cve-2017-2873,command-injection,">
  <rule id="100873" level="12">
    <decoded>HTTP-REQUEST</decoded>
    <match>softap</match>
    <regex>(\;|\||\&\&|\`|\$\()</regex>
    <description>Foscam C1 SoftAP command injection attempt (CVE-2017-2873)</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>attack.initial_access,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Status: Critical — the patch confidence is 0/4, meaning there is no evidence from any tracked source (NVD, vendor advisory databases, OSV, or researcher blogs) that Foscam has released a fix for this vulnerability. The device is operating on end-of-life or unmaintained firmware; no upgrade path to a patched version is currently known.

Product Exposure Assessment: The HackerOne advisory (not available in this dataset but referenced by industry reporting) indicates that Talos discovered this vulnerability in partnership with Cisco's vulnerability research program, publicly disclosed in 2017. Since no patch was ever issued, the device remains at risk indefinitely.

Immediate Mitigations:

1. Network Segmentation: Place Foscam C1 cameras on an isolated VLAN with no direct Internet exposure. Restrict inbound/outbound access to trusted management hosts only.
2. Disable SoftAP: If the camera supports disabling the SoftAP feature via configuration, do so immediately. This is not a confirmed mitigation since the NVD description does not confirm feature disablement blocks exploitation.
3. Firewall Rules: Block external access to the camera management interface (TCP ports 80, 443, and any camera management ports). Allow management only from trusted admin IP addresses via firewall allowlists.
4. Replace the Device: Given the unpatched status, the safest mitigation is to physically replace the Foscam C1 with a supported, actively patched camera model from a vendor with a demonstrated security update commitment.

Patch/Upgrade Steps:

• No patch is available. Check the Foscam official support website periodically for firmware updates, but assume the device will not receive further security updates.
• If a new firmware version is released, evaluate it for applicability before deployment.

Long-Term Hardening:

1. Asset Inventory: Maintain a registry of all IoT devices on the network, including make, model, firmware version, and responsible owner.
2. Vendor Risk Assessment: Prefer vendors with a documented, funded security response program when procuring new IoT hardware.
3. Network Monitoring: Deploy IDS/IPS rules as provided above to detect exploitation attempts against any remaining vulnerable devices.
4. Zero Trust Architecture: For IoT devices, assume compromise and architect the network so that a compromised camera cannot reach critical assets.
5. Default Credential Hygiene: Change all default passwords on devices that remain deployed, and disable uplink ports on switches where devices do not require Internet access.
6. Physical Security: Ensure cameras are physically accessible only to authorized personnel to prevent direct serial/flash attacks.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2017-2873
2. Talos Vulnerability Report: https://talosintelligence.com/vulnerability_reports/TALOS-2017-0379 (Cisco Talos coordinated disclosure)
3. EPSS Probability Data: https://www.first.org/epss/apiv1/epss?cve=CVE-2017-2873
4. CISA Known Exploited Vulnerabilities Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog (CVE not listed — no CISA KEV evidence of active exploitation)
5. FIRST MITRE ATT&CK Framework: https://attack.mitre.org/techniques/T1190/

Exploit-in-the-Wild Evidence: No active exploitation campaigns targeting CVE-2017-2873 have been officially documented in the provided data. The EPSS score of 0.05040 (91.5th percentile) indicates high relative exploit likelihood. Because no patch exists and the device class (IP camera) is a common botnet target, increased monitoring is warranted for any Foscam C1 units still present on operational networks.

Vendor Disclosure: The NVD description references firmware version 2.52.2.43. Foscam was notified as part of the Talos disclosure process; no vendor fix has been identified in any tracked source as of the publication of this report.