WebApp Sec mailing list archives
RE: SQL Injection Basics
From: "Keith Smith" <ksmith () firesnacks com>
Date: Mon, 10 Feb 2003 20:11:40 -0500
Robert: In ASP, what is equivalent to a prepared statement... i.e. must one use for example a Stored Procedure in MS SQL Server, or is there some ASP code level means of doing so... e.g. Recordsets etc. Any good sources for information here? Keith -----Original Message----- From: Robert Nilsen [mailto:rnilsen () catalystone com] Sent: Monday February 10, 2003 6:08 PM To: Taco Fleur; webappsec () securityfocus com Cc: Nick Jacobsen Subject: RE: SQL Injection Basics I might be missing the point here (and surely it must have been posted/explained before), but in my world, the safest way to do SQL is through prepared statements, a.k.a. bind variables/paramenters whenever someone out in the client segment has "touched" the input. Rule number one must always be to never thrust the client! And being sloppy just once with validation could mean the end of your data = not putting focus on security! By using prepared statements, the code is safer AND, in most cases, the next run will execute quicker. -Robert -----Original Message----- From: Taco Fleur [mailto:tacofleur () nella net au] Sent: 10. februar 2003 23:31 To: webappsec () securityfocus com Cc: Nick Jacobsen Subject: Re: SQL Injection Basics SQL Injection works only when 1. SELECT * FROM foo WHERE foobar = $var 2. SELECT * FROM foo WHERE foobar = '$var' In number 1, if the variable is not checked for the type of integer people can submit for example /urlstring/index.cfm?var=1; AND NASTY CODE HERE In number 2, if the variable is not checked for tick marks, and does not escape any that are found /urlstring/index.cfm?var=blah' AND NASTY CODE HERE -- In ColdFusion ALL ticks submitted are escaped, I'm sure more languages out there do that. Anyway, what I am after is the backdoor, the Unicode equivalent... Anyone? I got this %25%32%37 from Davy, which makes sense but still does not work with ColdFusion The following is the result SELECT category FROM mytable WHERE (category = '%27') I am trying to find all possible ways for SQL Insertion so I can protect myself against it. Like I said I already convert any charters like ' () < > to its HTML equivalent, but I beleive there is a way to get around this with Unicode, but not sure... ----- Original Message ----- From: "Nick Jacobsen" <nick () ethicsdesign com> To: <dhurst () spidynamics com>; <webappsec () securityfocus com> Sent: Tuesday, February 11, 2003 7:37 AM Subject: Re: SQL Injection Basics
Right, I wasn't thinking too well... makes sense. Though, according to quite a few SQL injection faqs I have read, it said that you could only inject code if the developer used tick marks. However, I just recently
used
SQL injection on some code where the developer used NO tick marks, but injection still worked if the injection string contained TWO tick marks. Was this just a fluke, or is it something that the faqs had wrong? Nick J. nick () ethicsdesign com ----- Original Message ----- From: "Dennis Hurst" <dhurst () spidynamics com> To: "'Nick Jacobsen'" <nick () ethicsdesign com> Cc: <webappsec () securityfocus com> Sent: Monday, February 10, 2003 8:59 AM Subject: RE: SQL Injection BasicsNick, Good question, but SQL Injection is absolutely an issue in VBScript (ASP pages). Here's the deal, the ' only acts as a comment if it's in the source code, not when it's in a variable. So... If you have code that looks like this: Dim sSql, rs, oConnection '..... Setup the connection...... sSql = "Select * from myCustomers where FirstName = '" & Request("txtFirstName") & "'" Set rs = oConnection.Execute(sSql) '.....do something with the returned data..... And a user puts a ' in the text box called txtFirstName you end up with something that acts like this: Dim sSql, rs, oConnection '..... Setup the connection...... sSql = "Select * from myCustomers where FirstName = '''" Set rs = oConnection.Execute(sSql) '.....do something with the returned data..... Have a great day, Dennis Hurst dhurst () spidynamics com SPI Labs -----Original Message----- From: Nick Jacobsen [mailto:nick () ethicsdesign com] Sent: Monday, February 10, 2003 6:07 AM To: Loki; raul.johhut () hushmail com Cc: webappsec () securityfocus com Subject: Re: SQL Injection Basics Hmm... just a gues here, but if a developer is using VBScript as the scripting language, would SQL injection be impossible, since in VBScript the " ' " mark is a comment mark, and therefore never used in SQL statements? Nick J nick () ethicsdesign com ----- Original Message ----- From: "Loki" <loki () fatelabs com> To: <raul.johhut () hushmail com> Cc: <webappsec () securityfocus com> Sent: Saturday, February 08, 2003 9:16 PM Subject: Re: SQL Injection BasicsRaul: SQL injection is not replacing the userid field in the url with"sdfsd",its escaping an SQL query with a single tick (') that the developer doesn't escape (or in the case of PHP, GLOBALS is turned on in the php.ini). SQL injection is simply altering the SQL query sent to the SQL server and executing an a malicious query instead of what was expected by the developer. Depending on the remote server (Oracle, Microsoft SQL,MySQL,PostgreSQL), these statements will only differ based on their stored procedures. Microsoft SQL containing the more fun procedure of (xp_cmdshell) :) e.g. 'SELECT * FROM USERS Username: ' or 1=1-- There are several papers available on SQL injection attacks, one in particular written by Chris Anley at http://www.nextgenss.com/research/papers.html Typically, you can quickly check web apps for vulnerability toinjectionby just entering a single tick (') in the form submission field,hittingsubmit, and looking for any errors such as ODBC, etc. Loki Fate Research Labs www.fatelabs.com On Sat, 2003-02-08 at 20:21, raul.johhut () hushmail com wrote:I am pen testing a webapp and am having some problems with SQLinjection.The app creates an ODBC error. Is this a garuntee of SQL Injection ? If I use www.victim/test.asp?userid=sfdsd the error is "inncorrect syntax near line 28 of test.asp" (or thatsthe English translation equiv in my case).I know the database is called master, and has a table test. What isthe syntax I should use ?What are the best freeware and open source tools for testing SQLinjection ? I tried WPosion which was OK.I also tried WebSleuth (which seems to have gone from GPL to closedsource commercial btw). Am I right is saying that the SQL plugin has to connect directly to the database to work ? I can only see port 80 so don't think this will work ?Thanks, Raul. Concerned about your privacy? Follow this link to get FREE encrypted email: https://www.hushmail.com/?l=2 Big $$$ to be made with the HushMail Affiliate Program: https://www.hushmail.com/about.php?subloc=affiliate&l=427-- Loki <loki () fatelabs com>
Current thread:
- Re: SQL Injection Basics, (continued)
- Re: SQL Injection Basics Loki (Feb 09)
- Re: SQL Injection Basics Nick Jacobsen (Feb 10)
- RE: SQL Injection Basics Forrest Lee Andrews (Feb 10)
- RE: SQL Injection Basics Dennis Hurst (Feb 10)
- Re: SQL Injection Basics Nick Jacobsen (Feb 10)
- Re: SQL Injection Basics Dave Aitel (Feb 10)
- RE: SQL Injection Basics Dennis Hurst (Feb 10)
- Re: SQL Injection Basics Taco Fleur (Feb 10)
- RE: SQL Injection Basics Robert Nilsen (Feb 10)
- Re: SQL Injection Basics Dirk Gomez (Feb 10)
- RE: SQL Injection Basics Keith Smith (Feb 10)
- Re: SQL Injection Basics Kevin Spett (Feb 10)
- Re: SQL Injection Basics Dejan Bosanac (Feb 11)
- Re: SQL Injection Basics Dirk Gomez (Feb 11)
- Re: SQL Injection Basics Dejan Bosanac (Feb 11)
- Re: SQL Injection Basics Nick Jacobsen (Feb 10)
- Re: SQL Injection Basics Loki (Feb 09)
- Re: SQL Injection Basics Sverre H. Huseby (Feb 11)
- Re: SQL Injection Basics dreamwvr () dreamwvr com (Feb 11)
- Re: SQL Injection Basics Sverre H. Huseby (Feb 11)
- Re: SQL Injection Basics dreamwvr () dreamwvr com (Feb 11)
- Re: SQL Injection Basics Sverre H. Huseby (Feb 11)
- Re: SQL Injection Basics Alex Russell (Feb 11)