CVE-2020-8867: OPCFoundation.NetStandard.Opc.Ua Insufficient Session Expiration And TOCTOU Vulnerability

MODERATE
Advisory Identifier: GHSA-9q94-v7ch-mxqw
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CVSS 7.5
CWE-613 CWE-367
Published
Advisory Summary

CVE-2020-8867 is a MODERATE (CVSS 7.5) insufficient session expiration and toctou vulnerability (CWE-613: Insufficient Session Expiration) affecting OPCFoundation.NetStandard.Opc.Ua libraries in the NuGet ecosystem. The issue involves insufficient session expiration and toctou race condition in opc foundation ua .net standard. Remediation is available by upgrading affected packages to version 1.4.359.31.

CVE-2020-8867 at a Glance

CVE Identifier CVE-2020-8867
GHSA Identifier GHSA-9q94-v7ch-mxqw
Severity MODERATE
CVSS v3.1 Base Score 7.5
CWE Classification CWE-613: Insufficient Session Expiration
Affected Product OPCFoundation.NetStandard.Opc.Ua
Package Ecosystem NuGet
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2020-8867

To remediate this vulnerability, upgrade all affected OPCFoundation.NetStandard.Opc.Ua dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

OPCFoundation.NetStandard.Opc.Ua fixed: 1.4.359.31 
Upgrade OPCFoundation.NetStandard.Opc.Ua to 1.4.359.31
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for OPCFoundation.NetStandard.Opc.Ua

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-8867, inspect your project dependencies for OPCFoundation.NetStandard.Opc.Ua:

inspect dependencies for OPCFoundation.NetStandard.Opc.Ua

Analyze the terminal output to locate any version of OPCFoundation.NetStandard.Opc.Ua in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.4.359.31), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-613: Insufficient Session Expiration, where according to wasc, "insufficient session expiration is when a web site permits an attacker to reuse old session credentials or session ids for authorization.". In OPCFoundation.NetStandard.Opc.Ua, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of OPC Foundation UA .NET Standard 1.04.358.30. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of sessions. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to create a denial-of-service condition against the application. Was ZDI-CAN-10295.

CVE-2020-8867 Affected OPCFoundation.NetStandard.Opc.Ua Versions

1 component(s)
Fixed Versions:
1.4.359.31
Product / Package Ecosystem Affected Versions Fixed Version
OPCFoundation.NetStandard.Opc.Ua
nuget/OPCFoundation.NetStandard.Opc.Ua
NuGet
< 1.4.359.31
1.4.359.31

References

NVD — CVE-2020-8867 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-8867
OPCFoundation.NetStandard.Opc.Ua Release RELEASE
https://github.com/OPCFoundation/UA-.NETStandard/releases/tag/1.4.359.31
OPCFoundation.NetStandard.Opc.Ua Security Information SECURITY
https://opcfoundation.org/SecurityBulletins/OPC%20Foundation%20Security%20Bulletin%20CVE-2020-8867.pdf
www.zerodayinitiative.com/advisories/zdi-20-5... WEB
https://www.zerodayinitiative.com/advisories/ZDI-20-536

Frequently Asked Questions

What is CVE-2020-8867?
CVE-2020-8867 is a security vulnerability in OPCFoundation.NetStandard.Opc.Ua involving Insufficient Session Expiration and TOCTOU Race Condition in OPC FOundation UA .Net Standard under CWE-613: Insufficient Session Expiration.
Which OPCFoundation.NetStandard.Opc.Ua versions are affected?
Affected versions include releases prior to 1.4.359.31 across affected packages: OPCFoundation.NetStandard.Opc.Ua.
What version fixes CVE-2020-8867?
Upgrading to 1.4.359.31 (or the latest patched release for your respective branch) resolves the vulnerability.
Is OPCFoundation.NetStandard.Opc.Ua affected?
Yes, OPCFoundation.NetStandard.Opc.Ua is affected in releases prior to 1.4.359.31. Upgrade your dependency to 1.4.359.31 or later.
What is the CVSS score of CVE-2020-8867?
CVE-2020-8867 has a CVSS v3.1 base score of 7.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2020-8867?
CVE-2020-8867 is classified under CWE-613: Insufficient Session Expiration (According to WASC, "Insufficient Session Expiration is when a web site permits an attacker to reuse old session credentials or session IDs for authorization.").
How can I check NuGet dependencies for CVE-2020-8867?
Run the dependency tree command: 'inspect dependencies for OPCFoundation.NetStandard.Opc.Ua'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9q94-v7ch-mxqw",
  "modified" : "2021-05-25T20:12:12Z",
  "published" : "2021-08-02T17:35:42Z",
  "aliases" : [ "CVE-2020-8867" ],
  "summary" : "Insufficient Session Expiration and TOCTOU Race Condition in OPC FOundation UA .Net Standard",
  "details" : "This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of OPC Foundation UA .NET Standard 1.04.358.30. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of sessions. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to create a denial-of-service condition against the application. Was ZDI-CAN-10295.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "OPCFoundation.NetStandard.Opc.Ua"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.4.359.31"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 1.4.358.30"
    }
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-8867"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/OPCFoundation/UA-.NETStandard/releases/tag/1.4.359.31"
  }, {
    "type" : "WEB",
    "url" : "https://opcfoundation.org/SecurityBulletins/OPC%20Foundation%20Security%20Bulletin%20CVE-2020-8867.pdf"
  }, {
    "type" : "WEB",
    "url" : "https://www.zerodayinitiative.com/advisories/ZDI-20-536"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-367", "CWE-613" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-25T20:12:12Z",
    "nvd_published_at" : "2020-04-22T21:15:00Z"
  }
}