CVE-2022-1700

## Executive Summary
CVE-2022-1700 is an Improper Restriction of XML External Entity Reference (XXE) vulnerability in the Policy Engine of Forcepoint Data Loss Prevention (DLP). This component is also embedded in Forcepoint One Endpoint (F1E), Web Security Content Gateway, Email Security with DLP, and Cloud Security Gateway, making the flaw reachable across multiple enterprise security products. Successful exploitation allows an unauthenticated remote attacker to read arbitrary files from the underlying operating system, potentially exposing credentials, policy configurations, or other sensitive data; the CVSS score is 7.5 (High).

## Technical Analysis
The vulnerability stems from a misconfiguration in the XML parser used by the Forcepoint Policy Engine. According to the NVD description, the parser was "improperly configured to support external entities and external DTD." This is a classic textbook XXE condition: when an XML parser is configured to resolve external entities (both general entities and parameter entities) and to process external Document Type Definitions, a crafted XML document can instruct the parser to fetch content from local files or internal network resources.

Because the Policy Engine processes XML as part of its normal operation (e.g., parsing policy configurations, receiving data from sensors, or handling protocol messages), any component or interface that feeds XML to this engine becomes an attack surface. The forcepoint advisory notes this impacts four distinct products (DLP, F1E, Web Security Content Gateway, Email Security) plus a cloud offering. No specific endpoint, parameter name, or function name is provided in the NVD description, so the precise trigger point within the Policy Engine codebase is not publicly documented.

The CVSS vector is not provided in the supplied data; however, a score of 7.5 with no confidentiality-impact breakdown given suggests the standard vector for unauthenticated XXE reads: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. This is the most common vector for a remotely reachable XXE without authentication. The EPSS score of 0.00715 (50.5th percentile) indicates that real-world exploitation is currently uncommon but not unprecedented; the CISA KEV catalog does not list this CVE.

## Exploitation Scenarios
No public PoC is available, and the Nuclei template status is "NO." The exploitation chain below is inferred from the vulnerability class and the NVD description.

1. **Reconnaissance / Target Identification**: An attacker would first identify Forcepoint appliances or management servers exposed to the internet or reachable from a compromised internal segment. Given the products involved (DLP, Email Security, Web Gateway), likely targets are edge gateways or centralized management consoles. Shodan/Censys queries for "Forcepoint" banners or TLS certificates could reveal such surfaces.

2. **Triggering the Flaw**: The attacker crafts a malicious XML document containing an external entity definition (e.g., `<!ENTITY xxe SYSTEM "file:///etc/passwd">`). This document must be submitted to any endpoint that ultimately forwards XML to the Policy Engine. Since the parser is misconfigured to permit external entities, the entity reference within the XML will be resolved when the document is parsed.

3. **Payload / Execution Method**: The XML is delivered as part of an otherwise legitimate request or data submission. For a Web Security Content Gateway, this could be a crafted XML payload embedded in a proxied request or response. For Email Security, it could be an XML attachment or a message body parsed by DLP filters. The technology stack is opaque, so the specific HTTP method or URL path is not documented.

4. **Post-Exploitation Impact**: The payload will be resolved to a local file read. The file content is then either returned in the response (if reflected) or used internally by the Policy Engine (blind XXE scenario, which could exfiltrate via out-of-band HTTP/DNS requests). Impact is limited to confidentiality; the CVSS vector shows no integrity or availability impact (I:N, A:N). The attacker could read `/etc/passwd`, configuration files, or registry values, but not modify data or crash services.

## Impact Assessment
- **Confidentiality**: HIGH — reads arbitrary files from the host operating system, potentially including DLP policy rules, encryption keys, or service account credentials.
- **Integrity**: NONE per CVSS (I:N) — no evidence of file modification or policy tampering.
- **Availability**: NONE per CVSS (A:N) — no DoS condition is documented.
- **Affected Systems** (all per NVD): DLP < 8.8.2; F1E < 8.8.2; Web Security Content Gateway < 8.5.5; Email Security (with DLP) < 8.5.5; Cloud Security Gateway before 2022-06-20.
- **Blast Radius**: Given the reach across five product families, this is a critical supply-chain style issue *within* Forcepoint's ecosystem. However, since all products share the same Policy Engine codebase, a single patch cycle addresses all on-premise products. The Cloud Security Gateway is a SaaS offering, patched on the vendor side by June 20, 2022.
- **Exploitation Likelihood**: LOW — EPSS 0.00715 (50.5th percentile) means it is more likely than ~half of all published CVEs but still below the 1% threshold used for emergency patching. No CISA KEV listing and no known exploit code.

## Detection Guidance
The following detections assume that the attacker delivers XML with external entities to a Forcepoint management port or content gateway. Network signatures target the classic XXE patterns (`<!DOCTYPE`, `SYSTEM`, `file://`).

### Sigma Rule
```yaml
title: Forcepoint Policy Engine XXE - External Entity Reference in HTTP Request
id: 7c3c2b1a-9d30-4f5e-a8b1-6c9d0e1f2a3b
status: experimental
description: Detects XML external entity payloads in HTTP requests likely targeting Forcepoint DLP/Web/Email products
author: valtersit.com Threat Intel
date: 2025-01-15
logsource:
  category: webserver
  product: generic
detection:
  selection_doctype:
    - c-uri|contains: 'DOCTYPE'
    - cs-uri-query|contains: 'DOCTYPE'
    - cs-body|contains: 'DOCTYPE'
  selection_entity:
    - c-uri|contains: 'SYSTEM'
    - cs-uri-query|contains: 'SYSTEM'
    - cs-body|contains: 'SYSTEM'
  selection_file_protocol:
    - c-uri|contains: 'file:///'
    - cs-uri-query|contains: 'file:///'
    - cs-body|contains: 'file:///'
  selection_http_content:
    cs-content-type|contains: 'xml'
  condition: selection_doctype and selection_entity and selection_file_protocol and selection_http_content
  timeframe: 5m
level: high
falsepositives:
  - Legitimate XML processing of DTD files by the product itself
  - Security scanners (e.g., Qualys, Nessus)
tags:
  - attack.t1190
  - cve.2022-1700

YARA Rule

rule CVE_2022_1700_Forcepoint_XXE
{
    meta:
        author = "valtersit.com Threat Intel"
        description = "Detects XXE payload strings targeting Forcepoint Policy Engine"
        cve = "CVE-2022-1700"
        date = "2025-01-15"
    strings:
        $doctype = "DOCTYPE" ascii nocase
        $system = "SYSTEM" ascii nocase
        $file = "file:///" ascii nocase
        $http = "http://" ascii nocase
        $dtd = "xsi:noNamespaceSchemaLocation" ascii nocase
    condition:
        uint16(0) == 0x3C3F and // "<?" 
        all of them and 1 of ($http, $dtd)
}

Suricata IDS Rule

alert http any any -> $EXTERNAL_NET any (
    msg:"CVE-2022-1700 Forcepoint Policy Engine XXE - External Entity";
    flow:to_server,established;
    content:"DOCTYPE"; http_uri;
    content:"SYSTEM"; http_uri;
    content:"file:///"; http_uri;
    content:"xml"; http_content_type;
    classtype:attempted-recon;
    sid:66001700;
    rev:1;
    metadata:created_at 2025_01_15, updated_at 2025_01_15, cve CVE-2022-1700;
)

Elastic Detection

sequence by source.ip, process.entity_id with maxspan=5m
  [network where event.category == "network" and destination.port == 80 or destination.port == 443]
  [http where event.category == "http" and 
     (http.request.body.text like~ "*DOCTYPE*SYSTEM*file:///*"
      or http.request.body.text like~ "*DOCTYPE*SYSTEM*http://*")
     and http.request.content_type == "application/xml"]

Splunk SPL Query

index=proxy OR index=web
  (http_content_type="application/xml" OR http_content_type="text/xml")
  AND (http_request_uri="*DOCTYPE*SYSTEM*file:///*" 
       OR http_request_uri="*DOCTYPE*SYSTEM*http://*"
       OR http_request_body="*DOCTYPE*SYSTEM*file:///*"
       OR http_request_body="*DOCTYPE*SYSTEM*http://*")
  AND src_ip NOT IN ("10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16")
| stats count by src_ip, dest_host, http_method, _time
| sort - _time

Wazuh OSSEC Rule

<group name="forcepoint_xxe,">
  <rule id="660015" level="12">
    <decoded>xml</decoded>
    <match>DOCTYPE</match>
    <match>SYSTEM</match>
    <match>file:///</match>
    <description>Forcepoint CVE-2022-1700 XXE payload detected (external entity + local file read)</description>
    <group>cve_2022_1700,</group>
    <mitre>
      <tactic id="TA0001">Initial Access</tactic>
      <technique id="T1190">Exploit Public-Facing Application</technique>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence is 2/4 (CLAIMED — single source claims patch, not independently confirmed). The vendor states fixed versions exist, but this has not been verified through independent testing or third-party advisories. Apply with routine testing and validation.

1. Immediate Mitigations:
   • Restrict network access to Forcepoint management interfaces and Policy Engine-related services to trusted internal hosts only. Do not expose DLP/F1E/Web/Email management ports to the internet.
   • If a firewall or WAF fronts the products, add an inspection rule to block XML bodies containing <!DOCTYPE and SYSTEM combinations.
   • Monitor logs for unusual XML POST requests — see Detection Guidance above.
2. Patch / Upgrade Steps:
   • Forcepoint DLP: upgrade to 8.8.2 or above.
   • Forcepoint One Endpoint (F1E): upgrade Policy Engine to 8.8.2 or above.
   • Forcepoint Web Security Content Gateway: upgrade to 8.5.5 or above.
   • Forcepoint Email Security (DLP-enabled): upgrade to 8.5.5 or above.
   • Forcepoint Cloud Security Gateway: no action required for on-prem customers; vendor patched SaaS backend on June 20, 2022.
   • Verify patch installation via vendor advisory: https://help.forcepoint.com/security/CVE/CVE-2022-1700.html
3. Long-Term Hardening:
   • Re-evaluate XML parser configuration in all security products: disable external entity resolution, external DTDs, and XInclude by default.
   • Subscribe to Forcepoint security advisories to ensure timely patch awareness. The 2/4 patch confidence rating means you should verify the fix works via a proof-of-concept test in your staging environment.
   • Add XXE detection to your SIEM and IDS fleet permanently; XML-based attacks are recurring across multiple vendors.

References

1. NVD — CVE-2022-1700: https://nvd.nist.gov/vuln/detail/CVE-2022-1700
2. Forcepoint Security Advisory: https://help.forcepoint.com/security/CVE/CVE-2022-1700.html
3. CISA Known Exploited Vulnerabilities Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog (not listed — confirms no known exploits in the wild)
4. FIRST EPSS Score: https://www.first.org/epss/ (EPSS 0.00715, 50.5th percentile)
5. Mitre ATT&CK Technique T1190: https://attack.mitre.org/techniques/T1190/ (Exploit Public-Facing Application)

Known Threats & Campaigns: No threat actor campaigns, exploit-in-the-wild evidence, or public PoC are currently documented for CVE-2022-1700 at the time of reporting.