CVE-2021-21479: Scimono server Remote Code Execution Vulnerability

HIGH
Advisory Identifier: GHSA-29q4-gxjq-rx5c
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CWE-917 CWE-62 CWE-59 CWE-690 CWE-74 CWE-77
Published
Advisory Summary

CVE-2021-21479 is a HIGH remote code execution vulnerability (CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')) affecting Scimono server libraries in the Maven ecosystem. The issue involves remote code execution in scimono. Remediation is available by upgrading affected packages to version 0.0.19.

CVE-2021-21479 at a Glance

CVE Identifier CVE-2021-21479
GHSA Identifier GHSA-29q4-gxjq-rx5c
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
Affected Product Scimono server
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2021-21479

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

com.sap.scimono:scimono-server fixed: 0.0.19 
<dependency>
    <groupId>com.sap.scimono</groupId>
    <artifactId>scimono-server</artifactId>
    <version>0.0.19</version>
</dependency>
Verify Direct and Transitive Dependencies

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

mvn dependency:tree -Dincludes=com.sap.scimono

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2021-21479, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=com.sap.scimono

Analyze the terminal output to locate any version of Scimono server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.0.19), your application is affected.

Note: The mvn dependency:tree -Dincludes=com.sap.scimono command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection'), where the product constructs all or part of an expression language (el) statement in a framework such as a java server page (jsp) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended el statement before it is executed. In Scimono server, 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

### Impact It is possible for attacker to inject and execute java expression and compromising the availability and integrity of the system. ### Patches The issue was fixed on [0.0.19 version](https://mvnrepository.com/artifact/com.sap.scimono/scimono-server/0.0.19)

CVE-2021-21479 Affected Scimono server Versions

1 component(s)
Fixed Versions:
0.0.19
Product / Package Ecosystem Affected Versions Fixed Version
com.sap.scimono:scimono-server
maven/com.sap.scimono/scimono-server
Maven
< 0.0.19
0.0.19

References

GitHub Advisory / Wiki ADVISORY
https://github.com/SAP/scimono/security/advisories/GHSA-29q4-gxjq-rx5c
NVD — CVE-2021-21479 NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-21479
Security Fix Commit FIX COMMIT
https://github.com/SAP/scimono/commit/413b5d75fa94e77876af0e47be76475a23745b80
mvnrepository.com/artifact/com.sap.sc... WEB
https://mvnrepository.com/artifact/com.sap.scimono/scimono-server/0.0.19

Frequently Asked Questions

What is CVE-2021-21479?
CVE-2021-21479 is a security vulnerability in Scimono server involving Remote Code Execution in SCIMono under CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection').
Which Scimono server versions are affected?
Affected versions include releases prior to 0.0.19 across affected packages: com.sap.scimono:scimono-server.
What version fixes CVE-2021-21479?
Upgrading to 0.0.19 (or the latest patched release for your respective branch) resolves the vulnerability.
Is scimono-server affected?
Yes, com.sap.scimono:scimono-server is affected in releases prior to 0.0.19. Upgrade your dependency to 0.0.19 or later.
What CWE is associated with CVE-2021-21479?
CVE-2021-21479 is classified under CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection') (The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.).
How can I check Maven dependencies for CVE-2021-21479?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.sap.scimono'. 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-29q4-gxjq-rx5c",
  "modified" : "2021-02-10T01:48:45Z",
  "published" : "2021-02-10T02:31:53Z",
  "aliases" : [ "CVE-2021-21479" ],
  "summary" : "Remote Code Execution in SCIMono",
  "details" : "### Impact\nIt is possible for attacker to inject and execute java expression and compromising the availability and integrity of the system.\n\n### Patches\nThe issue was fixed on  [0.0.19 version](https://mvnrepository.com/artifact/com.sap.scimono/scimono-server/0.0.19)",
  "severity" : [ ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "com.sap.scimono:scimono-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.0.19"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/SAP/scimono/security/advisories/GHSA-29q4-gxjq-rx5c"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2021-21479"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/SAP/scimono/commit/413b5d75fa94e77876af0e47be76475a23745b80"
  }, {
    "type" : "WEB",
    "url" : "https://mvnrepository.com/artifact/com.sap.scimono/scimono-server/0.0.19"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-59", "CWE-62", "CWE-690", "CWE-74", "CWE-77", "CWE-917" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-02-10T01:48:45Z",
    "nvd_published_at" : "2021-02-09T21:15:00Z"
  }
}