SUMMARY

A Denial of Service (DoS) exploit has been publicly released that can temporarily crash the awhost32 service for Symantec pcAnywhere. 

AFFECTED PRODUCTS

Note: Any user running a version of pcAnywhere earlier than 12.x is strongly advised to upgrade to the latest release, pcAnywhere 12.5 SP4 or pcAnywhere Solution 12.6.7

Upgrade instructions and build number identification are included in DOC5442,http://www.symantec.com/docs/DOC5442

• The hot fixes identified in TECH182142 have been back ported to support Symantec pcAnywhere 12.0.x and 12.1.x for customers currently unable to upgrade to Symantec pcAnywhere 12.5 SP4 or pcAnywhere Solution 12.6.7
• Symantec strongly recommends that customers upgrade at the first opportunity to the latest release of pcAnywhere 12.5 SP4 or pcAnywhere Solution 12.6.7
• If you are using an earlier version of Symantec pcAnywhere 12.5, SP1 or SP2, and have already applied all hot fixes, you WILL need to reapply the hot fixes identified in TECH182142 after upgrading to Symantec pcAnywhere 12.5 SP3

ISSUES

Medium

CVSS2 Base Score: 4.96

Impact 2.86, Exploitability 9.99

CVSS2 Vector:  (AV:N/AC:L/Au:N/C:N/I:N/A:P)

Exploits Publicly Available:  Yes

MITIGATION

Details
Symantec is aware of the public posting of a DoS exploit impacting Symantec pcAnywhere. An unexpected input to the awhost32 service can destabilize the service causing it to crash. In a normal installation the service automatically restarts.  A successful attack would result in a temporary loss of access to the affected system.

Symantec Response
Symantec engineers verified this on the supported versions identified above. A product update is available to address this DoS issue. Symantec engineers continue to review all functionality to further enhance the overall security of Symantec pcAnywhere.

If you are not currently able to move to the latest Symantec release; pcAnywhere 12.5 SP4 or pcAnywhere Solution 12.6.7, at least ensure you are running the most current hot fixes for your pcAnywhere application available from the following location:

For Enterprise, Small & Mid-Sized Business (SMB) - Download the appropriate update from TECH182142http://symantec.com/business/docs/TECH182142.

• TECH182142 provides the most current updated hot fix information to include all available patches that have been released for Symantec pcAnywhere 
• If you have already applied previous hot fixes you will still need to apply the latest TECH182142 hot fix to ensure you have all the latest updates.
• If  you have NOT applied previous Symantec pcAnywhere 12.5 SP3 hot fixes, then you need to apply all the TECH182142 hot fixes

LiveUpdate Option for Home and Home Office users of Symantec pcAnywhere 12.5.x:

• Symantec pcAnywhere 12.5.x  users who run automatic LiveUpdate will automatically receive updates to Symantec pcAnywhere 12.5 SP3 and all currently available hot fixes
• Users running Symantec pcAnywhere supported versions prior to 12.5.x (12.0.x or 12.1.x) will NOT receive these upgrades or hot fixes through LiveUpdate.  Symantec strongly recommends following guidance inTECH180597 for upgrading to pcAnywhere 12.5 SP3 and then apply all available updates

Symantec pcAnywhere 12.5.x users should run a manual LiveUpdate as follows to ensure they have the latest updates available:

• Open the Symantec pcAnywhere 12.5.x application
• Click Help > LiveUpdate
• Run LiveUpdate until all available product updates are downloaded and installed
• A system reboot may be required for the update to take affect

Once all updates have been applied, review update and build information found in TECH182142 to ensure you have updated your Symantec pcAnywhere application to the latest available build.  

Best Practices

Symantec recommends the following best practices when using remote access applications:

• Corporate firewalls should not allow inbound or outbound access without using VPN tunnels.
• When configuring a remote access application, establish policies around password strength, password retry limits.
• Always configure the application to require the user to approve all remote connections.

As part of normal best practices, Symantec strongly recommends:

• Restrict access to administration or management systems to privileged users
• Restrict remote access, if required, to trusted/authorized systems only
• Run under the principle of least privilege where possible to limit the impact of exploit by threats
• Keep all operating systems and applications updated with the latest vendor patches
• Follow a multi-layered approach to security. Run both firewall and anti-malware applications, at a minimum, to provide multiple points of detection and protection to both inbound and outbound threats

• Deploy network and host-based intrusion detection systems to monitor network traffic for signs of anomalous or suspicious activity. This may aid in detection of attacks or malicious activity related to exploitation of latent vulnerabilities

REFERENCES

Security Focus, http://www.securityfocus.com, has assigned the following Bugtraq ID

BID 52094 for the awhost32 denial of service

This issue is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. CVE ID CVE-2012-0292 has been assigned to this issue.

REVISION

4/9/2012 – Symantec released the latest version of pcAnywhere: pcAnywhere 12.5 SP4 and pcAnywhere Solution 12.6.7 which included many performance enhancements, all of the previous released security updates and enhancements to the security model of pcAnywhere.  Symantec recommends all pcAnywhere users move to the latest release of their respective product.