{
  "document": {
    "acknowledgments": [
      {
        "organization": "OSIsoft",
        "summary": "reporting this vulnerability to CISA"
      }
    ],
    "category": "csaf_security_advisory",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Disclosure is not limited",
      "tlp": {
        "label": "WHITE",
        "url": "https://us-cert.cisa.gov/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "This CSAF advisory was extracted from unstructured data and may contain inaccuracies. If you notice any errors, please reach out to the designated contact at CISA CSAF: central@cisa.dhs.gov",
        "title": "CISA Disclaimer"
      },
      {
        "category": "legal_disclaimer",
        "text": "All information products included in https://us-cert.cisa.gov/ics are provided \"as is\" for informational purposes only. The Department of Homeland Security (DHS) does not provide any warranties of any kind regarding any information contained within. DHS does not endorse any commercial product or service, referenced in this product or otherwise. Further dissemination of this product is governed by the Traffic Light Protocol (TLP) marking in the header. For more information about TLP, see https://us-cert.cisa.gov/tlp/.",
        "title": "Legal Notice"
      },
      {
        "category": "summary",
        "text": "Successful exploitation of this vulnerability could allow a remote authenticated attacker access to sensitive information or deliver false information.",
        "title": "Risk evaluation"
      },
      {
        "category": "other",
        "text": "Multiple Sectors",
        "title": "Critical infrastructure sectors"
      },
      {
        "category": "other",
        "text": "Worldwide",
        "title": "Countries/areas deployed"
      },
      {
        "category": "other",
        "text": "United States",
        "title": "Company headquarters location"
      },
      {
        "category": "general",
        "text": "CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.\nCISA also provides a section for control systems security recommended practices on the ICS webpage onus-cert.cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.\nOrganizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.",
        "title": "Recommended Practices"
      },
      {
        "category": "general",
        "text": "CISA also recommends users take the following measures to protect themselves from social engineering attacks:",
        "title": "Recommended Practices"
      },
      {
        "category": "other",
        "text": "No known public exploits specifically target this vulnerability.",
        "title": "Exploitability"
      }
    ],
    "publisher": {
      "category": "coordinator",
      "contact_details": "Email: CISAservicedesk@cisa.dhs.gov;\n Toll Free: 1-888-282-0870",
      "name": "CISA",
      "namespace": "https://www.cisa.gov/"
    },
    "references": [
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-21-313-06 JSON",
        "url": "https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2021/icsa-21-313-06.json"
      },
      {
        "category": "self",
        "summary": "ICS Advisory ICSA-21-313-06 Web Version",
        "url": "https://www.cisa.gov/news-events/ics-advisories/icsa-21-313-06"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://us-cert.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://us-cert.cisa.gov/ics/tips/ICS-TIP-12-146-01B"
      },
      {
        "category": "external",
        "summary": "Recommended Practices",
        "url": "https://us-cert.cisa.gov/ncas/tips/ST04-014"
      }
    ],
    "title": "OSIsoft PI Web API",
    "tracking": {
      "current_release_date": "2021-11-09T00:00:00.000000Z",
      "generator": {
        "engine": {
          "name": "CISA CSAF Generator",
          "version": "1.0.0"
        }
      },
      "id": "ICSA-21-313-06",
      "initial_release_date": "2021-11-09T00:00:00.000000Z",
      "revision_history": [
        {
          "date": "2021-11-09T00:00:00.000000Z",
          "legacy_version": "Initial",
          "number": "1",
          "summary": "ICSA-21-313-06 OSIsoft PI Web API"
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003c= 2019 SPI",
                "product": {
                  "name": "The following versions of PI Web API a data management platform are affected: All versions of PI Web API 2019 SPI and prior",
                  "product_id": "CSAFPID-0001"
                }
              }
            ],
            "category": "product_name",
            "name": "PI Web API"
          }
        ],
        "category": "vendor",
        "name": "OSIsoft LLC"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-43549",
      "cwe": {
        "id": "CWE-79",
        "name": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)"
      },
      "notes": [
        {
          "category": "summary",
          "text": "A remote authenticated attacker with write access to a PI Server could trick a user into interacting with a PI Web API endpoint and redirect them to a malicious website. As a result, a victim may disclose sensitive information to the attacker or be provided with false information.CVE-2021-43549has been assigned to this vulnerability. A CVSS v3 base score of 6.9 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N).",
          "title": "Vulnerability Summary"
        }
      ],
      "product_status": {
        "known_affected": [
          "CSAFPID-0001"
        ]
      },
      "references": [
        {
          "category": "external",
          "summary": "web.nvd.nist.gov",
          "url": "http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-43549"
        },
        {
          "category": "external",
          "summary": "www.first.org",
          "url": "https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N"
        }
      ],
      "remediations": [
        {
          "category": "mitigation",
          "details": "OSIsoft recommends upgrading to PI Web API 2021. Additional information can be found in the OSIsoft PI Web API security bulletin (registration required).",
          "product_ids": [
            "CSAFPID-0001"
          ],
          "url": "https://customers.osisoft.com/s/knowledgearticle?knowledgeArticleUrl=000037517"
        },
        {
          "category": "mitigation",
          "details": "Remove the OSIsoft.REST.Documentation.dll from the PI Web API installation directory.",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "The PI Web API installation directory is available at this registry entry:\\\\HKLM\\SOFTWARE\\PISystem\\WebAPI\\InstallationDirectory",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "The default PI Web API installation directory is:C:\\Program Files\\PIPC\\WebAPI Removing this file will cause built-in documentation to no longer be available. Navigating to the PI Web API endpoint with a browser will result in an error; however, the PI Web API will continue to function as a REST API",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "Documentation can be found at the OSIsoft website. Alternately, users are encouraged to limit access to PI Web API built-in documentation to dedicated development environments",
          "product_ids": [
            "CSAFPID-0001"
          ],
          "url": "https://docs.osisoft.com/"
        },
        {
          "category": "mitigation",
          "details": "Avoid adding authentication type \u201cAnonymous\u201d in PI Web API configuration settings to limit exposure to authenticated users only",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "Consider using a web application firewall to block html responses from PI Web API servers",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "Audit the AF hierarchy to ensure there are no unauthorized databases, elements, or attributes",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "For Kerberos authentication configurations, use Group Policy to deny network authentication to PI Server Administrator accounts on the PI Web API server.",
          "product_ids": [
            "CSAFPID-0001"
          ]
        },
        {
          "category": "mitigation",
          "details": "See the OSIsoft customer portal knowledge article for additional details and associated security updates (registration required).",
          "product_ids": [
            "CSAFPID-0001"
          ],
          "url": "https://customers.osisoft.com/s/knowledgearticle?knowledgeArticleUrl=Security-Alerts"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "baseScore": 6.9,
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N",
            "version": "3.0"
          },
          "products": [
            "CSAFPID-0001"
          ]
        }
      ]
    }
  ]
}