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TUCoPS :: Web :: Servers :: web5618.htm

Sun(TM) ONE / iPlanet Web Server 4.1 and 6.0 Remote Buffer Overflow
9th Aug 2002 [SBWID-5618]

	Sun(TM) ONE / iPlanet Web Server 4.1 and 6.0 Remote Buffer Overflow


	 Release Date: August 8, 2002



	 High (Remote SYSTEM/ROOT)


	 Systems Affected:

	 iPlanet 6.0 and prior



	 A vulnerability in transfer chunking can be exploited to remotely execute

	 code of an attacker's choice on a vulnerable machine. By sending a carefully

	 crafted session, an attacker can overwrite a section of the heap. Various

	 data structures in the overwritten heap can be manipulated to move attacker

	 supplied data to attacker supplied memory addresses, thereby altering the

	 flow of execution into an attacker supplied payload.


	 Note this variant is not the integer overflow affecting IIS and Apache that

	 was discovered during regression testing with Microsoft. This is another

	 variant relating to incorrect size calculation.


	 The following example will show the vulnerable condition:


	**************Begin Session****************

	POST /EEYE.html HTTP/1.1


	Transfer-Encoding: chunked

	Content-Length: 22






	**************End Session******************


	 [DATA] will overwrite heap memory. Increase or decrease depending on



	 Technical Description:

	 The example session above overwrites a section of the heap that contains

	 data structures related to the Memory management system. By manipulating the

	 content of these structures, we can overwrite an arbitrary 4 bytes of memory

	 with an attacker supplied address. 


	 It is widely assumed that the risk for these type of vulnerabilities is

	 fairly low due to the fact that addressing is dynamic and that you must use

	 brute force in your attack; however, this is false assumption and

	 exploitation can be successful with one attempt, across dll versions. An

	 attacker can overwrite static global variables, stored function pointers,

	 process management structures, memory management structures, or any number

	 of data types that will allow him to gain control of the target application

	 in one session.


	 Vendor Status:

	 Sun has released a security bulletin and patch:



	 Credit: Riley Hassell



	 Eli, Kasia, Halvar, FX, and the three amigos K2, Dark Spyrit, and Joey.


	 Copyright (c) 1998-2002 eEye Digital Security

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