CVE-2017-2878

Executive Summary

CVE-2017-2878 is a high-severity (CVSS 8.8) exploitable buffer overflow vulnerability in the web management interface of the Foscam C1 Indoor HD Camera running application firmware version 2.52.2.43. An unauthenticated remote attacker can trigger the vulnerability by sending a specially crafted HTTP request to the device, causing a buffer overflow that results in overwriting arbitrary data in memory. Successful exploitation can lead to remote code execution, complete compromise of the camera, and potential use of the device as a pivot point into the broader network. As of the time of this report, no official patch exists for this vulnerability, and affected devices remain exposed to exploitation.

Technical Analysis

The vulnerability exists in the web management interface of the Foscam C1 Indoor HD Camera, a widely deployed consumer-grade IP camera used for home and small business surveillance. The NVD description identifies that the affected firmware version is 2.52.2.43. The vulnerability is classified as a buffer overflow — a memory corruption condition where data written to a fixed-size buffer exceeds its allocated capacity, leading to adjacent memory being overridden.

Based on the NVD Description, the overflow is triggered by a "specially crafted HTTP request." This places the vulnerability in the class of network-reachable, remote-triggerable memory corruption flaws that are characteristic of embedded web servers handling user-supplied input without adequate bounds checking. While the exact vulnerable parameter or endpoint is not disclosed in the NVD description, the attack surface is the HTTP-based management interface, which is exposed on the default administrative port of the device (typically TCP 80 for HTTP, though the specific port is not named in the description).

Mechanism-level analysis proceeds within the buffer overflow class:

1. Input Handling: The embedded HTTP server receives a client-supplied HTTP request. Request elements such as URI path components, query string parameters, POST body fields, or HTTP headers are parsed for further processing.
2. Missing Boundary Validation: The parsing routine copies input into a stack- or heap-allocated fixed-size buffer without verifying that the input length does not exceed the buffer size.
3. Overflow Trigger: The oversized input overwrites adjacent memory regions, which may include the saved return address (stack overflow) or adjacent heap metadata (heap overflow). The NVD description explicitly states the overflow results in "overwriting arbitrary data."
4. Arbitrary Data Overwrite: The ability to overwrite arbitrary data suggests the attacker can control the overflow payload to corrupt critical pointers, return addresses, or function tables, ultimately enabling control-flow hijacking.

Precise technical details — including the affected function name, memory allocation type, or specific HTTP parameter — are not available in the provided NVD description. Insufficient technical detail available to identify the exact overflow location; the analysis above is based on the vulnerability class described in the advisory.

The web management interface is typically enabled by default on these devices and is reachable both from the local network and, when port forwarding is misconfigured, from the Internet. This makes the attack surface broad, especially for devices that remain on default settings.

Exploitation Scenarios

The following attack chain is inferred strictly from the NVD description and known patterns for the buffer overflow vulnerability class. No public PoC or exploit code is available at the time of writing; attack steps are described at the class level.

Campaign Profile: This vulnerability is likely leveraged in opportunistic campaigns targeting poorly secured IoT cameras, many of which are discoverable through Internet-wide scanning, with botnets and IoT-focused malware families being the probable carriers.

1) Reconnaissance / Target Identification

An attacker first identifies vulnerable Foscam C1 devices. Surface scanning via Shodan or similar services can identify devices by:

• HTTP banner reflecting "Foscam" or "C1" device signatures.
• Default web management interface accessible on the standard administrative TCP port.
• Common default credentials (often unchanged on consumer devices).

The attacker may also scan internal networks after initial foothold, using port scanning to locate web interfaces on IP cameras and other embedded devices.

2) Triggering the Flaw

The attacker crafts a specially structured HTTP request designed to overflow the vulnerable buffer. Because the exact vulnerable parameter is not disclosed, the attacker (or exploit developer) would fuzz the web interface's input handling routines to identify parameter length thresholds that cause memory corruption — a standard approach for unknown-parameter embedded vulnerabilities. On identifying the appropriate field, the attacker sends a request whose input exceeds the buffer length, causing memory corruption.

3) Payload / Execution Method

At the vulnerability-class level, the payload would contain:

• Padding bytes to fill the buffer to its boundary.
• Overwritten memory contents designed to hijack control flow — for example, overwriting a saved return address to redirect execution to attacker-controlled shellcode (stack overflow) or corrupting function pointers/data structures to achieve the same effect (heap overflow).

For MIPS- or ARM-based camera SoCs common in Foscam devices, shellcode or ROP chains would need to be architecture-specific. The "overwriting arbitrary data" capability in the NVD description implies that the attacker has substantial control over what gets written, favoring reliable exploitation.

4) Post-Exploitation Impact

Upon successful exploitation, the attacker achieves code execution with the privileges of the web management process — typically root or a privileged user on embedded camera firmware. The attacker can then:

• Disable or bypass authentication to gain persistent remote access.
• Pivot into the local network, using the camera as a stepping stone to reach other internal hosts.
• Enroll the camera into an IoT botnet for DDoS attacks (e.g., Mirai-style operations).
• Capture surveillance footage, undermining the camera's security purpose.
• Brick or reflash the device firmware, causing persistent denial of service.

No public PoC available; attack chain is inferred from vulnerability class.

Impact Assessment

CVSS Score: 8.8 (High) — The severity reflects the vulnerability's network-reachable nature, likely low attack complexity, no privilege requirement, and potentially severe confidentiality, integrity, and availability impact if exploited to gain code execution.

CISA KEV: NO — The vulnerability is not listed on CISA's Known Exploited Vulnerabilities catalog, suggesting limited zero-day or mass exploit evidence as of the latest catalog update. However, the EPSS score of 0.02077 places it at the 79.7th percentile, indicating that EPSS modeling assesses this vulnerability as having a higher-than-median probability of exploitation in the wild.

Business Impact:

• Confidentiality: Compromised cameras leak surveillance footage; adjacent network data may also be exposed via lateral movement.
• Integrity: Attacker can modify device firmware, alter configuration, or disable security monitoring.
• Availability: Device can be bricked, or its resources consumed by botnet activities.
• Lateral Movement: The camera becomes an internal foothold for attacking more critical enterprise systems, especially if the camera is deployed inside a corporate network segment.

Affected Systems: Foscam C1 Indoor HD Camera with application firmware 2.52.2.43. Without vendor confirmation, other firmware versions and the broader C1 product family may also be affected; affected-versions data is not enumerated in the NVD record.

Blast Radius: Any organization or household using this specific device model is at risk. The consumer positioning of the device suggests residential users are primary targets, but enterprise deployments for lobby or warehouse surveillance expose corporate networks to the same risk.

Detection Guidance

The following detection rules target exploitation attempts of CVE-2017-2878 based on the vulnerability class (buffer overflow via HTTP request). These rules are designed to detect anomalously large HTTP requests or malformed HTTP traffic directed at device management interfaces, which are the observable indicators of the exploitation technique.

Sigma Rule

title: Foscam C1 Buffer Overflow - Excessive HTTP Request Length
id: 7e0f8431-0bce-4d24-becb-c903ae025f7f
status: experimental
description: Detects HTTP requests with abnormally large URI or header sizes directed to management interfaces, potentially indicating buffer overflow attempts (CVE-2017-2878).
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2017-2878
author: Valtersit Threat Intel Team
date: 2025/05/10
tags:
    - attack.initial-access
    - attack.t1190
logsource:
    category: webserver
    product: generic
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem|startswith: '/'
    condition: selection
    filter_unknown:
        sc-status: 200
    # Placeholder threshold - adjust based on observed baseline
    threshold:
        field: c-uri
        value: 8192
falsepositives:
    - Legitimate large query strings in custom web applications
level: medium

YARA Rule

rule Foscam_C1_BufferOverflow_HTTP_Request
{
    meta:
        author = "Valtersit Threat Intel"
        description = "Detects oversized HTTP request patterns characteristic of CVE-2017-2878 exploitation attempts against Foscam C1 web management"
        cve = "CVE-2017-2878"
        date = "2025-05-10"
        severity = "high"

    strings:
        // Device fingerprint strings observed in Foscam web UIs
        $foscam_marker = "Foscam" ascii nocase
        $model_marker = "C1" ascii nocase
        $http_get = "GET " ascii
        $http_post = "POST " ascii

        // Long input markers - common buffer overflow probe signatures
        $long_aaa = { 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 }
        $long_00 = { 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 }

    condition:
        any of ($foscam_marker, $model_marker) and
        any of ($http_get, $http_post) and
        any of ($long_aaa, $long_00) and
        filesize < 10MB
}

Suricata IDS Rule

alert http any any -> $HOME_NET any (
    msg:"ET EXPLOIT Foscam C1 Buffer Overflow Attempt (CVE-2017-2878)";
    flow:to_server,established;
    content:"Foscam"; nocase; http.header_names;
    content:"GET"; http.method;
    content:"/"; http.uri;
    dsize:>8192;
    reference:cve,2017-2878;
    reference:url,nvd.nist.gov/vuln/detail/CVE-2017-2878;
    classtype:attempted-admin;
    sid:20270510;
    rev:1;
    metadata:attack_target IoT, created_at 2025_05_10, deployment Perimeter, former_category EXPLOIT, signature_severity Critical;
)

Elastic Detection

network where process.name == "httpd" and destination.port == 80 and
(
    (event.dataset == "apache.access" or event.dataset == "nginx.access")
    and url.path.len() > 8192
) or
(
    (network.protocol == "http" and http.request.bytes > 8192) and
    (http.request.body.content contains "Foscam" or url.path contains "Foscam" or http.request.referrer contains "Foscam")
)

Splunk SPL Query

index=web OR index=proxy sourcetype="access_combined" OR sourcetype="iis"
| where len(uri_path) > 8192 OR len(form_data) > 8192
| eval http_req_size = len(uri_path) + len(form_data)
| where http_req_size > 8192
| table _time, src_ip, dest_ip, uri_path, form_data, http_req_size, user_agent
| where like(uri_path, "%Foscam%") OR like(form_data, "%Foscam%") OR like(user_agent, "%Foscam%")

Wazuh OSSEC Rule

<group name="foscam,">
  <rule id="120850" level="12">
    <decoded>wazuh</decoded>
    <field name="url">\.url|\.uri</field>
    <regex>^.*(?:GET|POST|PUT|DELETE)\s+/\S+</regex>
    <description>Foscam C1 Buffer Overflow Attempt - Suspiciously Large HTTP Request (CVE-2017-2878)</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>exploit_attempt,</group>
  </rule>

  <rule id="120851" level="12">
    <if_sid>120850</if_sid>
    <field name="url\.request_length">@greater</field>
    <field name="url\.request_length">8191</field>
    <description>Foscam C1 Buffer Overflow Attempt - HTTP Request Exceeds 8KB Threshold</description>
    <group>exploit_attempt,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 0/4 — UNPATCHED. No patch evidence is available from any tracked source. The vendor (Foscam) has not published a firmware update addressing CVE-2017-2878 for the affected version. Organizations must assume the vulnerability persists.

1) Immediate Mitigations

• Network Segmentation: Place the camera on an isolated VLAN with strict egress filtering. Block outbound traffic from the camera to the Internet unless explicitly required for cloud features.
• Access Restriction: Restrict access to the web management interface to authorized administrative hosts only, using firewall ACLs or network allow-lists.
• Disable Remote Access: Disable UPnP port forwarding and any DMZ configuration that exposes the camera interface to the Internet.
• Change Default Credentials: Immediately change the default administrative password to a strong, unique credential to slow down opportunistic attackers.
• Firmware Quarantine: If firmware 2.52.2.43 cannot be replaced, consider taking the device offline or replacing it with a patched model.

2) Patch / Upgrade Steps

• Monitor Vendor Channels: Continuously monitor Foscam's official support and download pages for firmware updates that address buffer overflow vulnerabilities.
• Version Validation: Before applying any firmware, verify the release notes explicitly mention CVE-2017-2878 or "web management buffer overflow" fixes.
• Test Pre-Production: Apply the firmware to a non-critical device first and validate camera functionality before wide deployment.
• End-of-Life Consideration: If Foscam does not issue a patch in a timely manner, plan for hardware replacement with a vendor who has a demonstrated patch lifecycle for their IoT products.

3) Long-Term Hardening

• Network Monitoring: Deploy the detection rules above at network choke points to alert on anomalous HTTP traffic toward camera management interfaces.
• Patch Management Program: Establish an IoT patch management process that regularly audits all embedded devices in the enterprise, including cameras, for firmware currency.
• Procurement Policy: Include requirement for timely security patches and vulnerability disclosure processes in vendor evaluation criteria.
• Camera Replacement Schedule: For devices with confirmed critical vulnerabilities and no patch availability, initiate a replacement program to remove them from the environment within a defined timeline.
• Defense-in-Depth: Treat all IoT devices as untrusted. Segment them from the production network and monitor their behavior for signs of compromise.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2017-2878 — Official CVE record with description and CVSS score 8.8.
2. CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog — Confirmed CVE-2017-2878 is NOT listed in KEV, indicating no known mass exploitation as of the latest update.
3. FIRST EPSS: https://www.first.org/epss/ — EPSS score 0.02077 (79.7th percentile), indicating significant predicted exploit likelihood in the wild.
4. Foscam Official Site: https://www.foscam.com — Vendor product and support portal. Check for firmware updates addressing CVE-2017-2878; none identified as of this report date.
5. Shodan Search Reference: https://www.shodan.io — Recommended service for identifying exposed Foscam C1 devices on the Internet (search: "Foscam" http, or "Foscam C1").

Threat Actor / In-the-Wild Evidence: No known threat actor campaigns, ransomware groups, or APT activity specifically attributed to CVE-2017-2878 has been publicly documented. No exploit code or PoC is publicly available. However, the EPSS model places this at the 79.7th percentile of exploited CVEs, suggesting that exploit attempts in the wild are plausible. The vulnerability's buffer overflow nature makes it a strong candidate for incorporation into IoT botnet malware (Mirai-derived), which frequently exploits similar flaws in IP cameras. Organizations should treat unpatched Foscam C1 devices as significantly exposed.