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Topic: Format string attack

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	Foundations: What Are Buffer Overflows? Security Basics \| WatchGuard Technologies, Inc.
		That is the essence of a buffer overflow attack.
		Formatting means to take some data and prepare it for display or printing, but the formatting instructions are so flexible that some attackers have found ways of using formatting to write to memory.
		Format string attacks usually add a single address in memory that points to another address in memory where the attacker has added new instructions to execute.
	www.watchguard.com /infocenter/editorial/135136.asp (1743 words)

	Facts about topic: (Format string attack) (Site not responding. Last check: 2007-10-21)
		Format string attacks are a new class of vulnerabilities (additional info and facts about vulnerabilities) discovered in June of 2000 by Przemysław Frasunek and tf8, previously thought harmless.
		Format string attacks can be used to crash ((computer science) an event that causes a computer system to become inoperative) a program or to execute harmful code.
		Format string bugs most commonly appear when a programmer wishes to print a string containing user supplied data.
	www.absoluteastronomy.com /encyclopedia/f/fo/format_string_attack.htm (360 words)

	Format String Attack (Site not responding. Last check: 2007-10-21)
		A FormatStringAttack is a common class of attack on a CeeLanguage program that uses either the stdio functionality of the the ANSI C library (most commonly) or another system with similar functionality.
		The attack consists of providing a hostile format string which is then processed by the "printf engine", and which instructs said engine to do nasty things.
		The character % is used in printf format strings to specify output conversions.
	c2.com /cgi/wiki?FormatStringAttack (285 words)

	Format string attack - Definition, explanation
		Format string attacks are a new class of vulnerabilities discovered in June of 2000 by Przemysław Frasunek; and tf8, previously thought harmless.
		Format string attacks can be used to crash a program or to execute harmful code.
		Format string bugs most commonly appear when a programmer wishes to print a string containing user supplied data.
	www.calsky.com /lexikon/en/txt/f/fo/format_string_attack.php (322 words)

	Unix, Linux computers vulnerable to damaging new attacks \| CNET News.com
		"Format string bugs are the new trend in computer security vulnerabilities," said Ivan Arce, president of Argentinian security company Core SDI and discoverer of the "locale" format string vulnerability that became public last Friday.
		But the format string issue highlights the fact that weaknesses can lurk for years within software, and that it's hard to track them down among hundreds of thousands of lines of programming code.
		Format string vulnerabilities are similar to another broad class of problems called "buffer overflow," which have been around for decades and hinge on an attacker inserting too many characters into an input field such as a password prompt.
	news.com.com /2100-1001-245442.html (899 words)

	[No title]
		Format String Vulnerability User-supplied input from a GET request is used in a format string in a call to vsprintf(3s).
		A large field width is used to "inflate" the attack string, overflowing the destination argument of vsprintf(), placing code on the stack.
		Using a carefully crafted request string, it is possible to exploit the format string bug to print a pointer to the stack into the error log.
	www.cgisecurity.com /archive/webservers/dynaweb-httpd-format-string-pre-4.1a6-on-solaris.txt (835 words)

	[No title]
		Instead, the string is interpreted by the printf function as a format string.
		When the "%n" format is encountered in the format string, the number of characters output before the %n field was encountered is stored at the address passed in the next argument.
		As an example, to receive the offset to the space between two formatted numbers: int pos, x = 235, y = 93; printf("%d %n%d\n", x, &pos, y); printf("The offset was %d\n", pos); The "%n" format returns the number of characters that should have been output, not the actual count of characters that were output.
	community.core-sdi.com /~juliano/tn-usfs.txt (1880 words)

	Symantec Security Response - Glossary
		Attacks from multiple points: Injects malicious code into the.exe files on a system, raises the privilege level of the guest account, creates world read and writeable network shares, makes numerous registry changes, and adds script code into HTML files.
		It would not be unusual for this threat to attack the organization by deploying a common virus.
		A group that defines data formats and exchange procedures for sharing information of interest to intrusion detection and response systems, as well as to management systems that may need to interact with them.
	www.symantec.com /avcenter/refa.html (12123 words)

	[No title]
		address align and format string should be set by one's hand in detail (it means it's different from attack with 'brute forcing method') 3.
		environmental variables are read as a string before program started and it's also read as a common string (string is a sequential bytes that is ended by null 0x00).
		+ vul.c is format string vulnerable proggie which use "fgets()" for user input + vulex.sh is a script for attack, it's not brute force but hand made "hand made" means you have to set your own arbitrary format string with addresses and offset by yourself on your system.
	packetstorm.linuxsecurity.com /papers/unix/alpha-fmtstr.txt (1612 words)

	In space, no one can hear you groan - Salon
		The soul-deadening string of clichÃ©s that is "Attack of the Clones" must immediately be shot beyond Pluto where it can do no harm.
		"Star Wars: Episode II -- Attack of the Clones" could be the worst movie ever made and still it would have the faithful rallying around the Lucas franchise, brandishing their light sabers like bayonets.
		"Attack of the Clones" is barely reviewable as a movie because it's something so far beyond (and yet less than) anything an honest-to-God movie should be.
	www.salon.com /ent/movies/review/2002/05/16/attack_clones/index.html (886 words)

	Format String Attack (Site not responding. Last check: 2007-10-21)
		Format String Attacks are caused from the use of unfiltered user input as the format string parameter in certain C functions that perform formatting, such as printf().
		One may also write arbitrary data to arbitrary locations using the %n format token, which commands printf() and similar functions to write back the number of bytes formatted to an argument of type int *.
		By manipulating the stack by using spurious format tokens, this argument can be faked as part of the format string.
	www.javvin.com /networksecurity/FormatStringAttack.html (116 words)

	补天论坛-Small Buffer Format String Attack (Site not responding. Last check: 2007-10-21)
		When the ‘%s‘ format string is applied to the address 0x08048470 it would display the contents of that address.
		When attacking one other thing you need to know is the conversion for your shellcode address into decimal.
		If the format string is placed in argument 0 it will be stored on the stack and it will be stored closer in distance to the general environment variables.
	www.patching.net /bbs/viewgooddoc.asp?id=25843&bordid=4 (2156 words)

	Dr. Dobb's \| <h1>When Format Strings Attack! </h1> \| June 21, 2004
		In this example, the string in quotes is a format string and the format specifier %s tells the function to read the next argument (in this case the argv[1], the first command-line argument) and print it as a string.
		In the second case, the application used the input a_string%s as the format string and, thus, it was interpreted as the string a_string followed by the format specifier %s.
		Table 2 lists some other common C functions that use format strings and are vulnerable to this type of attack.
	www.ddj.com /184405774 (1847 words)

	Exploit Format String bugs on Alpha system
		This article describes format string attack in the limited situation on alpha system - i will call the operating systems which are based on alpha cpu as alpha systems.
		Exploit vulex.sh would attack to change.dtors's destructor routine address to our abitrary eggshell address, so that program would jump to there after end of all program routines.
		vulex.sh is a script for attack, it's not brute force but hand made "hand made" means you have to set your own arbitrary format string with addresses and offset by yourself on your system.
	doc.bughunter.net /format-string/alpha.html (1645 words)

	Core Security In the News
		By the insertion of format strings as part of a UIDL response message, the POP3 client can be forced to execute arbitrary commands.
		An attack is possible due to the lack of authentication methods applied to new downloaded packages.
		The attack is possible due to the lack of authentication methods applied to requests.
	www.coresecurity.com /common/showdoc.php?idxseccion=12&idx=331 (1046 words)

	SecuriTeam™ - DCE RPC Vulnerabilities New Attack Vectors Analysis
		Since the attack can be conducted over the UDP protocol and that it can be spoofed, it is easy to bypass common filtering rules.
		A protocol sequence is a "character string that represents a valid combination of an RPC protocol (such as ncacn), a transport protocol (such as TCP), and a network protocol (such as IP)" (see [MSDN]).
		Starting from a working attack to an RPC service it is trivial to adapt it to work over other protocol sequences.
	www.securiteam.com /windowsntfocus/6O00D1595E.html (1279 words)

	Jordo Media - View the feed - Security docs about Format String
		It describes how to find vulnerable C source code, and why format string vulnerabilities are more dangerous than common buffer overflows.
		This short paper written by lamagra explains what are format bugs, and how to exploit these flaws to run arbitrary code when the attacker can control the content of the format string parameter.
		This article shows various techniques that can be used in order to exploit format string vulnerabilities, through various examples.
	www.jordomedia.com /RSS/l_op=viewrss/lid=3141.html (520 words)

	US-CERT Cyber Security Bulletin SB06-296 -- Vulnerability Summary for the Week of October 16, 2006
		Format string vulnerability in the mod_tcl module 1.0 for Apache 2.x allows context-dependent attackers to execute arbitrary code via format string specifiers that are not properly handled in a set_var function call in (1) tcl_cmds.c and (2) tcl_core.c.
		Multiple unspecified vulnerabilities in Oracle Database 10.1.0.5 and 10.2.0.2 have unknown impact and remote authenticated attack vectors related to (1) Vuln# DB04 and sys.dbms_cdc_impdp in the (a) Change Data Capture (CDC) component; (2) Vuln# DB07, (3) DB08, and (4) DB16 in sys.dbms_cdc_isubscribe in CDC; and (5) mdsys.sdo_geor_int in the (b) Oracle Spatial component, aka DB12.
		Multiple unspecified vulnerabilities in XMLDB component in Oracle Database 9.2.0.7, 10.1.0.5, and 10.2.0.2 have unknown impact and remote authenticated attack vectors, aka (1) Vuln# DB14 and (2) DB15 related to xdb.dbms_xdbz.
	www.us-cert.gov /cas/bulletins/SB06-296.html (4098 words)

	ISS X-Force Database: dillo-capi-format-string(18807): Dillo capi.c format string attack
		Dillo is vulnerable to a format string attack, caused by a vulnerability in the a_Capi_ccc function in the capi.c file.
		GLSA 200501-11, Dillo: Format string vulnerability at http://www.gentoo.org/security/en/glsa/glsa-200501-11.xml.
		CVE-2005-0012: Format string vulnerability in the a_Interface_msg function in Dillo before 0.8.3-r4 allows remote attackers to execute arbitrary code via format string specifiers in a web page.
	www.iss.net /security_center/static/18807.php (279 words)

	[Format String Attack] Threat Classification - Web Application Security Consortium
		Format String Attacks alter the flow of an application by using string formatting library features to access other memory space.
		Vulnerabilities occur when user-supplied data are used directly as formatting string input for certain C/C++ functions (e.g.
		- Read character strings from the process' memory: If the output stream of the printf function is presented back to the attacker, he can read character strings at arbitrary memory locations by using the "%s" conversion character (and other conversion characters in order to reach specific locations).
	www.webappsec.org /projects/threat/classes/format_string_attack.shtml (332 words)

	Five common Web application vulnerabilities
		This article looks at five common Web application attacks, primarily for PHP applications, and then presents a case study of a vulnerable Website that was found through Google and easily exploited.
		Each of the attacks we'll cover are part of a wide field of study, and readers are advised to follow the references listed in each section for further reading.
		Covering SQL injection attacks in exhaustive detail is beyond the scope of this article, but below are a few good links in the references section which will help you to better understand this technique.
	www.securityfocus.com /infocus/1864 (1065 words)

	Format String - OWASP
		The data is passed as the format string argument to a function like sprintf(), FormatMessageW(), or syslog().
		It is also possible to use half-writes (%hn) to accurately control arbitrary DWORDS in memory, which greatly reduces the complexity needed to execute an attack that would otherwise require four staggered writes, such as the one mentioned in Example 1.
		Because the second parameter to syslog() is a format string, any formatting directives included in cmdBuf are interpreted as described in Example 1.
	www.owasp.org /index.php?title=Format_String&redirect=no (372 words)

	ISS X-Force Database: linuxnode-format-string(13077): LinuxNode format string attack
		LinuxNode versions prior to 0.3.2 are vulnerable to a format string attack.
		DSA-375-1, node -- buffer overflow, format string at http://www.debian.org/security/2003/dsa-375.
		CVE-2003-0708: Format string vulnerability in LinuxNode (node) before 0.3.2 may allow attackers to cause a denial of service or execute arbitrary code.
	xforce.iss.net /xforce/xfdb/13077 (245 words)

	Scan18
		Quoting from the CIAC advisory number K-069, rpc.statd attack is described as follows: "The rpc.statd passes user-supplied data and without validation of this data, a user may supply machine code to be executed with the privileges of the rpc.statd process".
		To help understand all the events took place during this attack, I also compiled this timeline of events for your reference (this timeline also included events I observed from analysing the network capture with a different filter, as stated in a later paragraph).
		By using a script to automate the recon of the potential target of attack, launch the attack and establish a connection to the vulnerable host, the cracker minimizes the time he/she spends.
	project.honeynet.org /scans/scan18/som/som13 (2558 words)

	Securiteam: [REVS] Small Buffer Format String Attack
		you are exploiting a format string with limited buffer space.
		string is near the environment variables that were loaded by the shell.
		Format string bugs are a method of abusing incorrect usage of the format...
	www.derkeiler.com /Mailing-Lists/Securiteam/2003-06/0008.html (1174 words)

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