Symantec VIP Access Desktop Arbitrary DLL Execution

SUMMARY

Symantec has released an update to address a finding in VIP Access Desktop that could allow a local user to force VIP Access Desktop UI Manager to execute an arbitrary formatted DLL with logged-on user privileges.

AFFECTED PRODUCTS

Symantec VIP Access Desktop

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CVE

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Affected Version(s)

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Remediation

CVE-2016-6593

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Prior to 2.2.2

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Upgrade to 2.2.3 or later

ISSUES

CVE-2016-6593

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Severity/CVSSv3:

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Low / 3.9 AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

References:

Impact:

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Securityfocus: BID 94731 / NVD: CVE-2016-6593

Code execution

Description:

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VIP Access Desktop UI Manager invokes DLLs from the current working folder during startup. A malicious local user can create specifically modified DLLs to replace the normal product DLLs required during startup. Then, by redirecting the startup path of the VIP Access Desktop UI Manager the user can cause the VIP Access Desktop UI Manager to invoke the substituted DLL instead of the required product DLL. Any specifically modified code execution could be performed with logged-on user privileges, which is normally user-level access in currently supported operating systems. Ultimately, this problem is caused by a failure to properly validate required product DLLs during start-up. This could result in a local user being able to manipulate VIP Access Desktop to load and execute an arbitrary DLL of the user's choice with user-level privileges.

MITIGATION

Symantec VIP Access Desktop has been updated to address this issue by implementing stricter access controls on authorized product-specific DLLs. Symantec VIP Access Desktop users should update to version 2.2.3, which is currently available for download from the VIP ID Center portal, https://idprotect.vip.symantec.com/desktop/download.v.

Best Practices

Symantec recommends the following measures to reduce risk of attack:

• Restrict access to administrative or management systems to authorized privileged users.
• Restrict remote access to trusted/authorized systems only.
• Run under the principle of least privilege, where possible, to limit the impact of potential exploit.
• Keep all operating systems and applications current with vendor patches.
• Follow a multi-layered approach to security. At a minimum, run both firewall and anti-malware applications 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 the detection of attacks or malicious activity related to the exploitation of latent vulnerabilities.

ACKNOWLEDGEMENTS

• John Page aka hyp3rlinx (CVE-2016-6593)