CIS CYBERSECURITY ADVISORIES

MS-ISAC ADVISORY NUMBER:
2015-088

DATE(S) ISSUED:
08/05/2015

SUBJECT:
Vulnerability in Apple's OS X Could Allow for Privilege Escalation

OVERVIEW:

A vulnerability has been discovered in Apple's OS X, which could allow for privilege escalation. Apple's OS X is an operating system for Apple computers. Successful exploitation of this vulnerability could allow an attacker to open, create, or modify files with root privileges which could result in the installation of malware or other unwanted programs, or the execution of arbitrary code.

THREAT INTELLIGENCE

There are reports of this vulnerability being exploited in the wild.

SYSTEM AFFECTED:

  • Apple's OS X version 10.10.4 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 Apple's OS X, which could allow for privilege escalation. The vulnerability exists in how the operating system handles the dyld dynamic linker and the DYLD_PRINT_TO_FILE environment variable. This vulnerability could allow for any file on the system to be opened or modified with root-like privileges. One such example could allow for the sudoers file to be modified to allow shell commands to be executed with root privileges without the need for a sudo password.

Successful exploitation of this vulnerability could allow an attacker to open, create, or modify files with root privileges which could result in the installation of malware or other unwanted programs, or the execution of arbitrary code.

RECOMMENDATIONS:

  • We recommend the following actions be taken:
  • Once a fix is released by Apple, update immediately after appropriate testing.
  • Remind users not to visit un-trusted websites or follow links provided by unknown or un-trusted sources.
  • Inform and educate users regarding the threats posed by hypertext links contained in emails or attachments, especially those from un-trusted sources.

REFERENCES:

Ars Technica:

http://arstechnica.com/security/2015/08/0-day-bug-in-fully-patched-os-x-comes-under-active-exploit-to-hijack-macs/

ZDNet:

http://www.zdnet.com/article/researcher-unveils-new-privilege-vulnerability-in-apples-mac-os-x/

http://www.zdnet.com/article/apple-mac-zero-day-flaw-hands-over-root-access-without-system-passwords/