CVE-2017-2879 Threat Intelligence Report

Executive Summary

CVE-2017-2879 is a buffer overflow vulnerability in the UPnP (Universal Plug and Play) implementation of the Foscam C1 Indoor HD Camera running firmware version 2.52.2.43. The vulnerability is triggered when the device processes a maliciously crafted UPnP discovery response, potentially allowing an attacker on the same subnet to overwrite arbitrary memory. With a CVSS score of 7.5 and no available patch, affected Foscam C1 cameras remain exposed to exploitation by any attacker who can reach the device's network segment.

Technical Analysis

Vulnerability Class: Buffer Overflow (CWE-120)

Affected Component: UPnP implementation in Foscam C1 Indoor HD Camera firmware 2.52.2.43

Attack Vector: Network-based, requires subnet adjacency

Mechanism:

The UPnP discovery protocol (SSDP - Simple Service Discovery Protocol) operates as follows:

1. Devices and clients multicast SSDP discovery messages to the standard UPnP multicast address on port 1900.
2. UPnP-enabled devices respond with unicast discovery responses containing device information.
3. The M-SEARCH discovery method is used to locate UPnP devices on the network.

The vulnerability exists in how the Foscam C1 camera processes UPnP discovery responses. When the camera issues a discovery request, it expects responses from other UPnP devices on the network. However, the firmware fails to properly validate the length of fields within the UPnP discovery response before copying them into fixed-size memory buffers. An attacker can craft a response packet with an oversized field that exceeds the allocated buffer size, causing a buffer overflow.

The NVD description states: "A specially crafted UPnP discovery response can cause a buffer overflow resulting in overwriting arbitrary data." This indicates that the overflow can be leveraged beyond simple denial-of-service — arbitrary data overwrite suggests the potential for code execution if an attacker can control the overflowing data and redirect execution flow.

Attack Surface Analysis:

• Network adjacency requirement: The attacker must be on the same subnet as the target camera. This limits remote exploitation but makes the attack highly relevant for:
  • Compromised adjacent hosts on the same LAN
  • Malicious IoT devices on the same network segment
  • Rogue access points providing network access to the camera's subnet
• The UPnP service typically runs as root or with elevated privileges on embedded devices, increasing the post-exploitation impact
• No authentication is required to trigger the vulnerability — UPnP discovery responses are processed without prior authentication

Technical Limitations:

Insufficient technical detail is available to identify the specific vulnerable functions, buffer sizes, or exact overflow offset. No public technical analysis has been published for this specific CVE.

Exploitation Scenarios

Prerequisites:

• Attacker and target Foscam C1 camera on the same Layer 2 network segment
• Target camera running firmware version 2.52.2.43
• No authentication required to trigger the vulnerability

Attack Chain:

Step 1: Reconnaissance / Target Identification

• The attacker scans the local subnet for UPnP-enabled devices using SSDP M-SEARCH requests
• Alternatively, the attacker can passively discover Foscam C1 cameras by monitoring network traffic for SSDP NOTIFY messages that cameras broadcast when joining the network
• Shodan-style dorking can identify exposed camera configurations, though local subnet access remains a requirement
• The attacker may also use ARP scanning or other network discovery techniques to map the subnet and identify camera devices

Step 2: Triggering the Vulnerability

• The attacker monitors network traffic for an outgoing UPnP discovery (M-SEARCH) from the target camera, OR triggers such traffic by sending a crafted SSDP request that causes the camera to issue its own discovery
• Once the target camera initiates a discovery, the attacker responds with a unicast UPnP discovery response containing a malformed field (e.g., Location header, Server header, or USN field) that exceeds the expected buffer length
• The camera's UPnP stack copies the oversized data into a fixed-size stack buffer, causing a buffer overflow

Step 3: Payload / Execution Method (Vulnerability-Class Level)

• Buffer overflow in the UPnP response parsing allows the attacker to overflow the target buffer and overwrite adjacent memory. At the vulnerability-class level, exploitation typically involves:
  • Overwriting a return address on the stack to redirect control flow to attacker-controlled data
  • Overwriting function pointers or other critical data structures in heap-based buffer overflows
  • Noting that the NVD description specifically mentions "overwriting arbitrary data," indicating the overflow gives the attacker substantial control over memory contents
• For embedded devices without modern memory protections (ASLR, DEP, stack canaries), direct shellcode injection is plausible
• Since no public exploit exists for this CVE, the exact exploitation technique remains unconfirmed

Step 4: Post-Exploitation Impact

• If code execution is achieved, the attacker gains arbitrary code execution in the context of the camera's process — typically root on embedded IoT devices
• Potential post-exploitation actions:
  • Install persistent backdoor for long-term access
  • Use the camera as a pivot point for further network penetration of the local network
  • Enable the camera's own streams and exfiltrate video feed
  • Enroll the camera into a botnet (e.g., Mirai-like harvesting of IoT devices)
  • Disable or brick the device as a denial-of-service action
• At minimum, the arbitrary data overwrite capability could be used to cause a persistent denial-of-service by corrupting critical firmware state

Note: No public PoC is available for this vulnerability; the attack chain is inferred from the vulnerability class and NVD description. Do not assume these exact exploitation techniques without further research.

Impact Assessment

CVSS Analysis (7.5 — HIGH):

Business Impact:

1. Surveillance Integrity Breach: Foscam C1 cameras are commonly deployed in residential and small business environments for indoor surveillance. A compromised camera can expose private video feeds and allow remote surveillance of the physical location.

2. Network Pivot Point: The camera becomes a beachhead on the local network. Attackers can pivot from the camera to attack other devices on the same subnet (PCs, servers, other IoT devices).

3. Regulatory/Compliance Issues: For business deployments, compromised surveillance cameras may violate privacy regulations and undermine compliance postures.

4. Botnet Recruitment: Unpatched IoT devices are prime candidates for inclusion in botnets. The attack vector (subnet-adjacent) aligns with botnet propagation techniques.

Affected Systems & Blast Radius:

• Foscam C1 Indoor HD Camera — firmware version 2.52.2.43 specifically
• Other Foscam models or firmware versions have not been confirmed affected, though UPnP implementations are often shared across product lines — insufficient data to confirm extended impact
• Blast radius limited to devices on the same subnet until post-exploitation movement occurs; after that, scope expands to the entire network

EPSS Note: EPSS score of 0.00818 (53.9th percentile) indicates that while no active mass exploitation is currently observed, the vulnerability is ranked above median in terms of exploitation likelihood.

Detection Guidance

Sigma Rule

title: Foscam C1 UPnP Buffer Overflow Attempt Detection
id: 8c7f3a2e-5d94-4b61-9e83-1a7d5c8e93f2
status: experimental
description: Detects potentially malicious UPnP discovery responses targeting Foscam C1 cameras, indicative of CVE-2017-2879 exploitation attempts
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2017-2879
tags:
    - attack.initial-access
    - attack.t1190
logsource:
    category: network
    product: suricata
    definition: 'Network IDS/IPS logs from Suricata or Zeek'
detection:
    selection_udp:
        destination.port: 1900
        protocol: udp
    selection_anomaly:
        - length: "> 1500"
          description: 'Oversized UPnP response packets'
        - payload contains: "HTTP/1.1 200 OK"
    filter_benign:
        - payload contains: "Ubuntu"
        - payload contains: "Windows"
        - payload contains: "Linux/"
    condition: selection_udp and selection_anomaly and not filter_benign
level: high
falsepositives:
    - Legitimate but unusual UPnP responses from non-standard devices
    - Network devices sending verbose SSDP responses
fields:
    - source.ip
    - destination.ip
    - destination.port
    - packet.length
    - payload

YARA Rule

rule Foscam_C1_UPnP_Exploit_CVE_2017_2879
{
    meta:
        author = "Valter IT Security Research"
        date = "2024"
        description = "Detects UPnP discovery responses with patterns indicative of CVE-2017-2879 exploitation attempts"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2017-2879"
        severity = "high"
        cve = "CVE-2017-2879"
    strings:
        $http_ok = "HTTP/1.1 200 OK"
        $ssdp_locations = /LOCATION:\s*http:\/\/[^\r\n]{150,}/ nocase
        $ssdp_servers = /SERVER:\s*[^\r\n]{100,}/ nocase
        $ssdp_extra_headers = /(ST|USN|CACHE-CONTROL|SERVER|LOCATION):\s*[^\r\n]{255,}/ nocase
        $upnp_ssdp_reply = "ssdp:discover" nocase
        $msearch_trigger = "M-SEARCH * HTTP/1.1" nocase
        $foscam_user_agent = /User-Agent:.*[Ff]oscam/ nocase
    condition:
        uint16(0) == 0x4500 // IPv4 packet
        and filesize > 500
        and $http_ok and $ssdp_locations and $ssdp_extra_headers
        and (#ssdp_extra_headers > 2)
        and not $msearch_trigger // Response, not request
        and ( $foscam_user_agent or UPnP_anomaly )
}

Suricata IDS Rule

alert udp any any -> any 1900 (msg:"CVE-2017-2879 Foscam C1 UPnP Buffer Overflow Attempt"; content:"HTTP/1.1 200 OK"; depth:13; content:"LOCATION"; within:100; content:"!"; pcre:"/^.{0,150}LOCATION.{0,300}\r?\n/"; flow:to_server; classtype:attempted-user; sid:1002879; rev:1; reference:cve,2017-2879;)

Elastic Detection

sequence by source.ip, destination.ip
  [ network where protocol == "udp" and destination.port == 1900
    and network.direction == "inbound" ]
  [ network where protocol == "udp" and destination.port == 1900
    and network.direction == "outbound"
    and network.packets >= 1 ]
  [ network where protocol == "udp" and destination.port == 1900
    and network.direction == "inbound"
    and network.bytes > 1500 ]
  [ network where network.protocol == "udp" and destination.port == 1900
    and network.direction == "inbound"
    and network.bytes > 5000 ]

Splunk SPL Query

index=network sourcetype=suricata OR sourcetype=zeek
    dest_port=1900 proto=udp
    | eval packet_size = if(sourcetype="suricata", length, if(sourcetype="zeek", orig_bytes, 0))
    | where packet_size > 1500
    | search "*HTTP/1.1 200 OK*" OR "*LOCATION:*"
    OR
index=firewall sourcetype=netflow
    dst_port=1900 protocol=udp
    | stats count by src_ip, dst_ip, bytes_out, packets_out
    | where bytes_out > 5000
    | table _time, src_ip, dst_ip, bytes_out, packets_out, count
    | sort - _time
    | head 100

Wazuh OSSEC Rule

<group name="ids,">
    <rule id="401241" level="10">
        <decoded_as>json</decoded_as>
        <field name="event_type">drop</field>
        <field name="dest_port">1900</field>
        <field name="proto">UDP</field>
        <field name="alert.signature">CVE-2017-2879</field>
        <description>Possible Foscam C1 UPnP buffer overflow exploitation attempt (CVE-2017-2879)</description>
        <group>network_attack</group>
        <mitre>
            <id>T1190</id>
        </mitre>
    </rule>

    <rule id="401242" level="8">
        <decoded_as>json</decoded_as>
        <field name="event_type">alert</field>
        <field name="dest_port">1900</field>
        <field name="proto">UDP</field>
        <description>UPnP traffic anomaly detected on port 1900</description>
        <group>network_alert</group>
    </rule>

    <rule id="401243" level="12">
        <decoded_as>json</decoded_as>
        <field name="event_type">alert</field>
        <field name="dest_port">1900</field>
        <field name="proto">UDP</field>
        <field name="payload_size">gt 5000</field>
        <description>Large UDP payload to port 1900 (potential UPnP buffer overflow)</description>
        <group>network_exploitation</group>
        <mitre>
            <id>T1190</id>
        </mitre>
    </rule>
</group>

Mitigation & Patch Guidance

Patch Status: UNPATCHED — No vendor fix available

Based on patch confidence assessment of 0/4, there is NO evidence of any patch from the vendor (Foscam), no firmware update, and no workaround documentation. The Foscam C1 camera running firmware 2.52.2.43 remains permanently vulnerable.

1. Immediate Mitigations (Defense-in-Depth)

Network Segmentation:

• Isolate all Foscam C1 cameras on a dedicated VLAN or subnet separate from user workstations and critical servers
• Strictly firewall the camera subnet from the rest of the network — allow only necessary outbound traffic (e.g., NTP, remote access via VPN if required)

Block UPnP Traffic:

• Disable UPnP discovery/SSDP entirely at the network level if cameras do not require it. Block UDP port 1900 and TCP port 49152 (UPnP control)
• On managed switches/routers, implement layer 2 ACLs to block UDP port 1900 between device VLANs

Network Access Controls (NAC):

• Implement 802.1X port-based authentication on network switches to prevent unauthorized devices from joining the network segment where cameras are deployed
• Monitor for new devices joining the network — the attack requires subnet adjacency, so preventing rogue devices reduces exposure

Intrusion Detection:

• Deploy the detection rules above (Suricata/Sigma/Elastic/Splunk) on the network boundary or on a SPAN port capturing the camera VLAN
• Alert on XSS/SSDP anomalies and undersized/oversized UPnP packets

Firewall Rules:

• Block all incoming UDP port 1900 traffic to cameras from hosts other than authorized UPnP control points
• If UPnP is not used, block entirely: iptables -A INPUT -p udp --dport 1900 -j DROP

Firmware Updates:

• Check regularly at https://www.foscam.com/downloads/firmware.html for updated firmware for the C1 model
• Given the age of this CVE (2017) and lack of patch after all this time, it is likely that the vendor has abandoned the C1 model — do not expect a fix

2. Patch / Upgrade Steps

As there is no patch available for this exact vulnerability, the following steps are recommended:

1. Replace the hardware: Retire Foscam C1 cameras running firmware 2.52.2.43 and replace with a supported camera from a vendor with an active security update program
2. If replacement is not possible immediately: Consider disabling the camera's network access entirely, or using it only in an air-gapped environment where physical access is restricted
3. Check for later firmware versions: It is possible (but unconfirmed from tracked sources) that later firmware versions addressed the UPnP component even without an explicit CVE advisory. Consult the vendor and test carefully — installing unverified firmware introduces its own risk
4. Contact the vendor: Open a support ticket with Foscam asking specifically for the status of CVE-2017-2879 and whether any firmware update addresses it

3. Long-term Hardening

Purchase Criteria:

• When replacing cameras, select products that commit to security patch availability (e.g., major vendors with published CVE response policies)
• Verify the vendor uses secure coding practices — specifically, validate that UPnP/SSDP implementations properly bounds-check network inputs

IoT Security Architecture:

• Adopt a zero-trust model for IoT/OT: no device is implicitly trusted on a network, even an internal one
• Deploy IoT monitoring tools that profile device behavior and flag anomalous network traffic (e.g., unusual UDP traffic patterns from cameras)
• Document all devices on the network — know what is deployed, where, and what it communicates with

Network-wide UPnP Policy:

• Develop and enforce a network-wide policy to disable UPnP on all devices unless explicitly justified and mitigated
• Use vulnerability scanning (Nessus, OpenVAS) to continuously scan for devices with known CVEs like CVE-2017-2879

Continuous Monitoring:

• Maintain a threat-specific watch for this CVE — since EPSS percentile is above average (53.9%), exploitation likelihood is non-trivial
• Monitor threat intelligence feeds for any public PoC release or in-the-wild exploitation reports

References

1. NVD Entry:
   https://nvd.nist.gov/vuln/detail/CVE-2017-2879
   Official NVD description of the vulnerability including the formal vulnerability details.

2. Foscam Official Website:
   https://www.foscam.com/downloads/firmware.html
   Official firmware download page — monitor for security updates for C1 model.

3. CISA Known Exploited Vulnerabilities Catalog:
   https://www.cisa.gov/known-exploited-vulnerabilities-catalog
   CVE-2017-2879 is NOT listed — no confirmed in-the-wild exploitation has been catalogued as of this writing.

4. MITRE ATT&CK:
   https://attack.mitre.org/techniques/T1190/
   Exploit Public-Facing Application technique — the primary tactic associated with this vulnerability's exploitation chain.

5. FIRST CVSS Calculator:
   https://www.first.org/cvss/calculator/3.0
   Reference for CVSS vector string interpretation and scoring breakdown.

Report Metadata

• Analyst: Valter IT Security Research Team
• Date: 2024
• Status: FINAL
• TLP: AMBER — Distribution limited to enterprise security teams
• Confidence: MEDIUM — Vulnerability details confirmed via NVD; exploitation details inferred from vulnerability class due to lack of public technical analysis

DISTRIBUTION: Authorized for internal security team use at VALTER IT and partner organizations. Do not redistribute outside your organization without review of the TLP classification and need-to-know basis.