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HomeResourcesAdvisoriesA Vulnerability in GNU C Library Could Allow for Arbitrary Code Execution

A Vulnerability in GNU C Library Could Allow for Arbitrary Code Execution

MS-ISAC ADVISORY NUMBER:

2018-017

DATE(S) ISSUED:

02/05/2018

OVERVIEW:

A vulnerability has been discovered in the GNU C Library (glibc), which could allow for arbitrary code execution. This library is required in all modern distributions of Linux as it defines the system calls and other basic facilities used in the Linux kernel. Successful exploitation of this vulnerability could result in an attacker gaining the same privileges as the exploited application. Depending on the privileges associated with the application, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. If this application has been configured to have fewer user rights on the system, exploitation of this vulnerability could have less impact than if it was configured with administrative rights. Failed exploit attempts could lead to a denial of service condition for the affected application.

THREAT INTELLIGENCE:

There are currently no reports of this vulnerability being exploited in the wild. However, a proof of concept exploit has been publically released.

SYSTEMS AFFECTED:

  • GNU C Library versions 2.26 and prior

RISK:

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

TECHNICAL SUMMARY:

A vulnerability has been discovered in the GNU C Library, which could allow for arbitrary code execution. Specifically, this is an integer overflow vulnerability due to internal memalign() and malloc() functions in glibc failing to properly report allocation errors. This vulnerability can be exploited when the system processes maliciously crafted data.

Successful exploitation of this vulnerability could result in an attacker gaining the same privileges as the exploited application. Depending on the privileges associated with the application, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. If this application has been configured to have fewer user rights on the system, exploitation of this vulnerability could have less impact than if it was configured with administrative rights. Failed exploit attempts could lead to a denial of service condition for the affected application.

RECOMENDATIONS:

We recommend the following actions be taken:

  • Apply appropriate patches provided by the affected *nix distribution to the vulnerable systems immediately after appropriate testing.
  • Run all software as a non-privileged user (one without administrative privileges) to diminish the effects of a successful attack.

REFERENCES:

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