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DoS Flaw Affects Symantec Endpoint Products

DoS Vulnerability Affects Symantec Endpoint Protection (SEP) and Norton Products on Windows

Symantec has recently patched a denial of service (DoS) vulnerability that plagued its Norton Security’s Portable Executable file scanning functionality. 

The security flaw, tracked as CVE-2016-5308 could be exploited during the parsing of a special crafted portable executable file, the researchers warn. Because the faulting code is located in the IDSvix86 kernel driver, the parsing of the PE file can cause an access violation in the IDSvix86 driver, which would result in denial of service.

Discovered by Piotr Bania of Cisco Talos, the vulnerability was tested on version of Symantec Norton Security and on DSvix86 driver version To successfully exploit the vulnerability, an attacker would have to send the victim a crafted file with a large SizeOfRawData field in a section header, Talos says.

“The parser does not check to make sure that this is within the bounds of the file, or MD5Compress which is the function that causes the segfault, therefore if the parameter is big enough, it can cause the MD5Compress function to access memory which is currently unavailable causing the machine to crash,” Talos explains in a blog post.

In an advisory detailing the vulnerability, Symantec says that the issue is located in the Client Intrusion Detection System (CIDS) driver, which could cause a system crash when interacted with a specially-crafted PE file. The company also reveals that the bug affects not only the Windows version of the Norton Security, but also Symantec Endpoint Protection.

According to Symantec, the security flaw has a CVSS:3.0 base score of 5.0 and is considered Medium severity because the attacker would have to trick the user to download the malformed PE file and then manipulate it to interact with the vulnerable CIDS engine. Talos’ advisory, on the other hand, claims that the vulnerability has a CVSS:3.0 score of 7.5.

The Cisco Talos team explains that they worked with Symantec to responsibly disclose the vulnerability. However, while the team warned Symantec on this vulnerability at the end of May, a patch for the issue wasn’t released until July 7, when the security flaw was also made public.

Norton Security users can stay protected by updating to CIDS v15.1.2 via LiveUpdate Defs, while Symantec Endpoint Protection customers should update to CIDS v15.0.6 to ensure they are kept safe.

In May, Google Project Zero researcher Tavis Ormandy discovered an issue related to how the Symantec AVE parses executable files packed by the ASPack executable file compressor and revealed that Symantec Endpoint Antivirus, Norton Antivirus, Symantec Email Security and Symantec Scan Engine were affected. The Critical flaw could allow for remote code execution when a specially crafted file was sent to the victim.

Over the past several months, the researcher has analyzed the security products offered by various firms, including Trend Micro, ComodoKaspersky Lab, AVGAvast and others, and revealed multiple vulnerabilities in them.


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