CVE-2020-1959: Syncope core Expression Language Injection Vulnerability

CRITICAL
Advisory Identifier: GHSA-vjqw-r3ww-wj2w
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CVSS 9.8
CWE-917
Published
Advisory Summary

CVE-2020-1959 is a CRITICAL (CVSS 9.8) expression language injection vulnerability (CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')) affecting Syncope core libraries in the Maven ecosystem. The issue involves expression language injection in apache syncope. Remediation is available by upgrading affected packages to version 2.1.6.

CVE-2020-1959 at a Glance

CVE Identifier CVE-2020-1959
GHSA Identifier GHSA-vjqw-r3ww-wj2w
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
Affected Product Syncope core
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

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:H/I:H/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 High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2020-1959

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

org.apache.syncope:syncope-core fixed: 2.1.6 
<dependency>
    <groupId>org.apache.syncope</groupId>
    <artifactId>syncope-core</artifactId>
    <version>2.1.6</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=org.apache.syncope

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2020-1959, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.apache.syncope

Analyze the terminal output to locate any version of Syncope core in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.1.6), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.apache.syncope 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 Syncope core, 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

A Server-Side Template Injection was identified in Apache Syncope prior to 2.1.6 enabling attackers to inject arbitrary Java EL expressions, leading to an unauthenticated Remote Code Execution (RCE) vulnerability. Apache Syncope uses Java Bean Validation (JSR 380) custom constraint validators. When building custom constraint violation error messages, they support different types of interpolation, including Java EL expressions. Therefore, if an attacker can inject arbitrary data in the error message template being passed, they will be able to run arbitrary Java code.

CVE-2020-1959 Affected Syncope core Versions

1 component(s)
Fixed Versions:
2.1.6
Product / Package Ecosystem Affected Versions Fixed Version
org.apache.syncope:syncope-core
maven/org.apache.syncope/syncope-core
Maven
< 2.1.6
2.1.6

References

NVD — CVE-2020-1959 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-1959
Syncope core Security Information SECURITY
http://syncope.apache.org/security

Frequently Asked Questions

What is CVE-2020-1959?
CVE-2020-1959 is a security vulnerability in Syncope core involving Expression Language Injection in Apache Syncope under CWE-917: Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection').
Which Syncope core versions are affected?
Affected versions include releases prior to 2.1.6 across affected packages: org.apache.syncope:syncope-core.
What version fixes CVE-2020-1959?
Upgrading to 2.1.6 (or the latest patched release for your respective branch) resolves the vulnerability.
Is syncope-core affected?
Yes, org.apache.syncope:syncope-core is affected in releases prior to 2.1.6. Upgrade your dependency to 2.1.6 or later.
What is the CVSS score of CVE-2020-1959?
CVE-2020-1959 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2020-1959?
CVE-2020-1959 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-2020-1959?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.apache.syncope'. 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-vjqw-r3ww-wj2w",
  "modified" : "2021-07-29T16:57:05Z",
  "published" : "2021-06-16T17:18:58Z",
  "aliases" : [ "CVE-2020-1959" ],
  "summary" : "Expression Language Injection in Apache Syncope",
  "details" : "A Server-Side Template Injection was identified in Apache Syncope prior to 2.1.6 enabling attackers to inject arbitrary Java EL expressions, leading to an unauthenticated Remote Code Execution (RCE) vulnerability. Apache Syncope uses Java Bean Validation (JSR 380) custom constraint validators. When building custom constraint violation error messages, they support different types of interpolation, including Java EL expressions. Therefore, if an attacker can inject arbitrary data in the error message template being passed, they will be able to run arbitrary Java code.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.apache.syncope:syncope-core"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.1.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-1959"
  }, {
    "type" : "WEB",
    "url" : "http://syncope.apache.org/security"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-917" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-25T20:59:03Z",
    "nvd_published_at" : "2020-05-04T13:15:00Z"
  }
}