A Vulnerability in Apache Struts Could Allow for Remote Code Execution

MS-ISAC ADVISORY NUMBER:

2020-161

DATE(S) ISSUED:

12/08/2020

OVERVIEW:

A vulnerability has been discovered in Apache Struts, which could allow for remote code execution. Apache Struts is an open source framework used for building Java web applications. Successful exploitation of this vulnerability could allow for remote code execution. Depending on the privileges associated with the user, an attacker could then install programs; view; change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

THREAT INTELLIGENCE:

There are currently no reports of this vulnerability being exploited in the wild.

SYSTEMS AFFECTED:

  • Apache Struts versions prior to 2.5.26

RISK:

Government:
  • Large and medium government entities: HIGH
  • Small government entities: MEDIUM
Businesses:
  • Large and medium business entities: HIGH
  • Small business entities: MEDIUM
Home Users:
LOW

TECHNICAL SUMMARY:

A vulnerability has been discovered in Apache Struts, which could allow for remote code execution. This vulnerability exists due to some of the tag attributes performing a double evaluation if a developer applied forced OGNL evaluation by using the %{…} syntax. Using forced OGNL evaluation on untrusted user input can lead to remote code execution and security degradation. Successful exploitation of this vulnerability could allow for remote code execution. Depending on the privileges associated with the user, an attacker could then install programs; view; change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights.

RECOMMENDATIONS:

We recommend the following actions be taken:

  • Upgrade to the most recent version of Apache Struts after appropriate testing.
  • Verify no unauthorized system modifications have occurred on the system before applying the patch.
  • Frequently validate type and content of uploaded data.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.

REFERENCES:

Information Hub : Advisories


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Pencil Newsletter 14 Jan 2021
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