Rule

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Sid
15571

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Summary:
This event is generated when an attempt is made to exploit a known vulnerability in Helix Server.

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Impact:
Denial of Service. Information disclosure. Loss of integrity. 

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Detailed Information:
Multiple buffer overflows in RealNetworks Helix Server and Helix Mobile Server 11.x before 11.1.8 and 12.x before 12.0.1 allow remote attackers to (1) cause a denial of service via three crafted RTSP SETUP commands, or execute arbitrary code via (2) an NTLM authentication request with malformed base64-encoded data, (3) an RTSP DESCRIBE command, or (4) a DataConvertBuffer request.

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Affected Systems:
RealNetworks Helix Server 11.0
RealNetworks Helix Server 12.0.0

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Attack Scenarios:
Many types of buffer overflow exist, this is a generic term that may apply to many circumstances that result in an overflow of some kind. A parameter overflow for example, means that the attacker is able to supply data as a parameter to the execution of a program. When the program expands the supplied data, if the size of the parameter is not correctly checked, it may exceed a set limit allowing the attacker to overflow the buffer and write data into memory.
In a stack overflow, the attacker has the opportunity to overwrite a return memory address which allows them to point the return address to a memory location containing code they wish to execute. This allows the attacker to run code with the full privileges of the program in use. The attacker may also supply the address for a known important call, for example the system() call, with the arguments to the call on the stack. The stack also contains the stack pointer and the frame pointer, overwriting these values may lead to a write-what-where condition.
In a heap overflow, it is possible to overwrite function pointers that may be in memory. This may allow the attacker to execute code in memory by changing the function pointer to move to code of their choosing. This can occur even in programs that do not necessarily use function pointers since they may be left in memory at run time. The heap also contains user data which also becomes visible to the attacker.

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Ease of Attack:
Simple. Exploits exist.

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False Positives:
None known.

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False Negatives:
None known.

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Corrective Action:
Upgrade to the latest non-affected version of the software.

Apply the appropriate vendor supplied patches.

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Contributors:
Sourcefire Vulnerability Research Team
This document was generated from data supplied by the National Vulnerability Database. A product of the National Institute of Standards and Technology.
For more information see http://nvd.nist.gov/

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Additional References:

NIST CVE-2008-5911:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2008-5911
 
Common Weakness Enumeration:
http://cwe.mitre.org/data/definitions/120.html
 
Common Attack Pattern Enumeration and Classification:
http://capec.mitre.org/data/definitions/100.html

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