27 December 2011

Injection

Posts relating to the category tag "injection" are listed below.

27 December 2011

Guide to HTML5 Web Security

Further to my previous notes about HTML 5 security, a superb reference document was published earlier this month.

An extract from a page in Michael Schmidt's document HTML5 Web Security showing how HTML5 vulnerabilities and attacks are described and illustrated in diagrammatic form

Michael Schmidt (Compass Security) wrote his master's thesis about HTML5 security in May 2011 and has published an extract for everyone to access.

HTML5 Web Security describes issues, vulnerabilities, threat & attack scenarios and countermeasures across 80 pages including numerous well thought-out diagrams, and is backed up with detailed references and an appendix full of attack details.

The main sections are:

  • 2.2 Cross-origin resource sharing
  • 2.3 Web storage
  • 2.4 Offline web application
  • 2.5 Web messaging
  • 2.6 Custom scheme and content handlers
  • 2.7 Web sockets API
  • 2.8 Geolocation API
  • 2.9 Implicit relevant features of HTML5
    Web workers, new elements, attributes and CSS, Iframe sandboxing and server-sent events

If you are already developing HTML, or planning to, read this document as soon as possible and update your requirements documents, specifications, design documents, coding standards, and test plans to incorporate the knowledge.

The document would be worth buying if it were a book, but it has generously been made available publicly. Yes, I am still reading the document, and so far have only one very minor complaint — it would be good to have a content list. Maybe in version 1.1?

Posted on: 27 December 2011 at 09:07 hrs

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11 October 2011

SQL Injection For Beginners

SQL injection is one of those attacks which most developers have heard of, but may not be familiar with.

Photograph of a workstation in a retail shop showing a web browser and a message printed across the top of the display screen 'PUBLIC NOTICE: This computer is for staff use only.'

I stumbled upon some really good guidance on doing some of your own homework on learning about SQL injection. Best Damn Quick Tips for a Total SQL Injection Newbie (Period) quickly describes three steps (reading, setting up a vulnerable web environment and mimicking attackers) to go from little to lots of knowledge. Yes, really do this on your own test vulnerable applications — never start trying things out on applications or systems you are not authorised to examine.

Then for the last step which is to research defensive measures, the best resource is the OWASP SQL Injection Prevention Cheat Sheet. Happy reading!

Posted on: 11 October 2011 at 06:59 hrs

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09 September 2011

Secure Web Application Development and Implementation

The UK's Centre for the Protection of National Infrastructure (CPNI) has updated its guidance on protecting business applications with the publication this month of a new document on developing and implementing secure web applications.

Partial image of the title sheet from the Centre for the Protection of National Infrastructure CPNI guidance document 'Development and Implementation of Secure Web Applications', published in August 2011

Development and Implementation of Secure Web Applications is a well-written and digestible 81-page A4 document arranged in seven main sections:

  • Introduction to web application security
  • General aspects of web application security
  • Access handling (authentication, session management and access control)
  • Injection flaws
  • Application users and security
  • Thick client security
  • Preparing the infrastructure

It appears to replace the good, but somewhat dated document "Briefing 10/2006 - Secure web Applications - Development, Installation and Security Testing" created by their predecessor National Infrastructure Security Co-ordination Centre (NISCC), and issued in April 2006. The new document is more compact and focused, and I think I prefer it. Yes of course it is more up-to-date, and while it would be possible to argue why some things are included and not others, these others things tend to be explained further in the references. It's clear there is considerable overlap with information from OWASP and the Microsoft SDL, but I'm sure the reverse is true to an extent too.

It is very encouraging CPNI have taken the time to produce an updated document, but that probably reflects the types of risks facing their audience. I am especially pleased to see the section on infrastructure, since application security cannot be an island on its own. I would say the guidance is probably on the medium-to-heavy weight side of advice, but that is probably appropriate for critical national infrastructure, and the document does discuss threat modelling initially. It might seem overwhelming to some organisations new to the subject, and that might need some help on what to do first.

I think the document could perhaps do with more cross-referencing to additional information resources elsewhere. Yes, documents can always be improved, and I am sure we will find niggles and faults with use, but threats evolve and so does our knowledge.

Posted on: 09 September 2011 at 20:00 hrs

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12 July 2011

Cross Site Scripting Video Tutorial

The OWASP AppSec Tutorial Series has been extended with the publication of a new tutorial about cross site scripting (XSS), probably the most common vulnerabilities in web applications.

Partial screen capture of a frame from Jerry Hoff's new episode on cross site scripting in the OWASP AppSec Tutorial Series

The tutorial series project develops fast-moving educational videos which are short enough to capture the main concepts and issues in a very accessible manner. The series now comprises the following episodes:

  1. Introduction
  2. Injection Attacks
  3. [Stored] Cross-Site Scripting

Project lead, author, narrator and editor Jerry Hoff has produced these videos with great flair, and I would recommend them as introductions to application security concepts in security awareness training. Watch out for future episodes.

Posted on: 12 July 2011 at 16:12 hrs

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22 April 2011

State of Software Security Report Volume 3

The third semi-annual "State of Software Security Report - The Intractable Problem of Insecure Software" has been issued by Veracode (see my previous comments on volume 1 and volume 2).

Partial view of one of the figures in Veracode's report State of Software Security - Volume 3 Volume 3 provides further insight into the results of static binary, dynamic, and manual security testing of almost 5,000 applications over the last 18 months from Veracode's wide client base. The data covers both web and non-web application code in the most common programming languages: C/C++, ColdFusion, Java, .NET and PHP.

This report provides even more data on the types of vulnerabilities found and further comparison between applications by industry sector, company type, purpose, supplier type and time to acceptable quality. There is a wealth of statistics which will be useful to anyone looking to reduce software vulnerabilities including developers, testers and those in the information security industry. I'm particularly impressed by the thought that has gone into the design of the data-rich charts and the honesty about whether trends are statistically significant.

One aspect mentioned is that newer applications tested on first time submission are not much better than older ones (in this case "older" means "a year or so ago"). The reasons suggested are either lack of secure development practices, or such practices were performed but inadequately. But I wonder if this may be the result of Veracode's customers beginning to work backwards through their legacy applications, to assess and thus rank them for remediation effort? Therefore, these legacy applications will not have had the same degree of care and attention as perhaps more recently developed software.

The mine of information presented over 50 pages also discusses the relatively low level of security knowledge of developers, and the need to provide better awareness and training. But a new section in this report attempts to examine the remediation efforts. I really appreciate the effort that has gone into this and the presentation of so much data analysis. We have to thank Veracode's customers for allowing their data to be included in this aggregated data.

The report also discusses how there is a growing usage of third-party risk assessments, where the software is assessed independently using multiple testing techniques. In some sectors, software suppliers are increasingly being held accountable for the security quality of the applications they produce. I think that is a good thing.

While there is a comparison of different sectors, I wonder if it will be possible to delve greater into some details in future? For example, some large providers of outsourced development are also active in the software security space, and have their own products for static & dynamic security testing, and even provide software security consultancy services. Do those companies take their own medicine? Do they apply the knowledge and tools they offer in another part of their business in their own software development services? We probably won't find out any time soon, but it would be fascinating to know.

The report's data suggests web applications are still plagued by vulnerabilities such as cross-site scripting (XSS), information leakage and injection (SQL injection as CRLF injection). Meanwhile the most frequently found issues for non-web applications are buffer overflow, error handling and potential backdoors. Cryptographic issues are also very common. The majority of applications tested suffer from these well-known defects, and all of which are well documented and have a range of methods to solve them.

Good reading for the beach this weekend!

Posted on: 22 April 2011 at 12:45 hrs

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17 September 2010

OWASP AppSec Ireland 2010 - Part 2

After arriving in Dublin last night, I walked to Trinity College this morning and had a little time for a coffee and to greet people I knew before we moved into the lecture theatre.

Photograph from the presentation at AppSec Ireland 2010

Following the welcome to OWASP Ireland 2010 by Eoin Keary, Fabio Cerullo & Rahim Jina of the OWASP Ireland Board, John Viega delivered a thought-provoking keynote speech on "Application Security in the Real World". John described real-world problems and approaches to application security need to prove their value. He described seven practices: awareness & training, assessments & audits, development & Q&A, vulnerability response, operational security, compliance and security metrics which, when applied appropriately can demonstrate a return on investment.

Photograph from the presentation at AppSec Ireland 2010

OWASP Board members Eoin Keary & Dinis Cruz provided an overview of OWASP's current status, its activities including many of its projects and of the global committees. They described how OWASP's mission "is to make application security VISIBLE for buyers and INVISIBLE for developers". Samy Kamkar was given a brief slot to describe how cross site scripting (XSS) can be used against user's routers to eventually gain the MAC address and ultimately a user's geolocation using Google data.

Photograph from the presentation at AppSec Ireland 2010

After a short break and opportunity to look at the sponsor booths, the conference split into two streams for the rest of the morning. Fred Donovan spoke on the topic of "Counter Intelligence as a Defense", describing how gathering information and taking approved action can help identify, assess and potentially neutralise threats to an organisation's ability to conduct business, and to enhance the protection of corporate assets and customer data. He also described sources of information including web application firewalls (WAFs), server logs, application logs, the media, list servers, MITRE, honeypots and from the source of the threat itself. some of the impediments and do's and dont's in this pro-active approach.

Photograph from the presentation at AppSec Ireland 2010

Ryan Berg gave a lively and fast-paced description on the "Path to a Secure Application". He described what isn't working, and the need to mitigate the damage that attackers can do, rather than assuming you can keep them outside your network, He provided numerous examples of how security can be built into to all stages of the software development process, but made the point that organisations should make efforts to improve their existing application development processes, rather than creating new ones.

Photograph from the presentation at AppSec Ireland 2010

Dan Cornell described how Android and iPhone smartphone applications are coded, deployed and, how and when the source code can be reverse engineered. He presented an example Android application and some tools to demonstrate how embedded URLs, file paths and host names can be extracted to help determine its workings. He recommended that, like other applications, smartphone applications should undergo threat modelling, care should be taken on what information is stored and where, and to be careful when consuming any third-party services, and ensure that enterprise web services are approved and deployed securely.

Photograph from the presentation at AppSec Ireland 2010

After lunch which was held in the beautiful Dining Hall of Trinity College Dublin, Professor Fred Piper (Royal Holloway College) presented the second keynote on "The changing face of cryptography". Prof Piper described that people do not need to attack algorithms when they can attack the implementation or cryptographic system instead. He provided an engaging and personable talk about algorithms, implementation weaknesses, real-life cryptography and the related political and social issues, clearly demonstrating his wide and deep knowledge.

Tyler Shields' presentation "Application Security Scoreboard in the Sky" described the results from Veracode's State of Software Security, which I have discussed before but is worth remembering as a good source of information when building business cases for secure development processes. The first volume had examined the differences between open source, commercial and out-sourced software. The second volume is due to be released in the next fortnight.

Photograph from the presentation at AppSec Ireland 2010

Rory Alsop & Rory McCune (co-chairs of OWASP Scotland) "The 'Real' Application Security Pentest." described why penetration test companies and purchasers of their services need to understand the requirements clearly and to make best use of the budget. They described that penetration testing is increasingly being used but there are inconsistencies in how it is undertaken and customers don't always receive what they want. The speakers described common myths and what buyers should do.

Photograph from the presentation at AppSec Ireland 2010

Vinay Bansal and Martin Nystrom jointly presented Cisco's experiences of "How to Defend Fragile Web Applications". Cisco know they are constant attack on their perimeter, but they have to concentrate their resources on defending DMZ & internal systems and minimising the damage from compromises. Cisco use architectural assessments, developer training, secure coding techniques, verification practices and more recently using web application firewalls (WAFs) in a reverse proxy mode using Apache httpd, ModSecurity and ModProxy. They described the problems and benefits of using WAFs in front of Cisco's tens of thousands of applications, and how they are trialling using the WAFs for virtual patching, where the applications cannot be modified.

Photograph from the presentation at AppSec Ireland 2010

The final keynote "Hackers and Hollywood: The Implications of the Popular Media Representation of Computer Hacking" was presented by Damian Gordon (School of Computing, Dublin Institute of Technology). Damian gave a light-hearted look at "Hackers and Hollywood: The Implications of the Popular Media Representation of Computer Hacking". He has researched whether or not movies accurately portray hackers and the implications of that portrayal, based on filtering 200 potential movies down to 50 clearly relating to computer hackers and not just cyberpunk, sci-fi or where hacking is only a peripheral activity. The conclusion? Movies are doing quite well but are missing out on some hacking features such as denial of service, phishing, organisation identuty theft and e-harassment of employees. Maybe next year?

Congratulations for a very successful and informative day to all the organisers, helpers and speakers. A little late, but off to the social event...

Posted on: 17 September 2010 at 19:26 hrs

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02 July 2010

Web Site Security Basics for SMEs

Sometimes when I'm out socially and people ask what I do, the conversation progresses to concerns about their own web site. They may have a hobby site, run a micro-business or be a manager or director of a small and medium-sized enterprise (SME)—there's all sorts of great entrepreneurial activity going on.

It is very common for SMEs not to have much time or budget for information security, and the available information can be poor or inappropriate (ISSA-UK, under the guidance of their Director of Research David Lacey, is trying to improve this). But what can SMEs do about their web presence—and it is very unusual not to have a web site, whatever the size of business.

Photograph of a waste skip at the side of St John Street in Clerkenwell, London, UK, with the company's website address written boldly across it

Last week I was asked "Is using <company> okay for taking online payments?" and then "what else should I be doing?". Remember we are discussing protection of the SME's own web site, not protecting its employees from using other sites. If I had no information about the business or any existing web security issues, this is what I recommend checking and doing before anything else:

  • Obtain regular backup copies of all data that changes (e.g. databases, logs, uploaded files) and store these securely somewhere other than the host servers. This may typically be daily, but the frequency should be selected based on how often data changes and how much data the SME might be prepared to lose in the event of total server failure.
    • check backup data can read and restored periodically
    • don't forget to securely delete data from old backups when they are no longer required
  • Use a network firewall in front of the web site to limit public (unauthenticated user) access to those ports necessary to access the web site. If other services are required remotely, use the firewall to limit from where (e.g. IP addresses) these can be used.
    • keep a record of the firewall configuration up-to-date
    • limit who can make changes to the firewall
  • Ensure the host servers are fully patched (e.g. operating system, services, applications and supporting code), check all providers for software updates regularly and allow time for installing these.
    • remove or disable all unnecessary services and other software
    • delete old, unused and backup files from the host servers
  • Identify all accounts (log in credentials) that provide server access (not just normal web page access), such as used for transferring files, accessing administrative interfaces (e.g. CMS admin, database and server management/configuration control panels) and using remote desktop. Change the passwords. Keep a record of who has access and remove accounts that are no longer required and enable logging for all access using these accounts.
    • restrict what each account can do as much as possible
    • add restrictions to the use of these accounts (e.g. limit access by IP address, require written approval for use, keep account disabled by default)
  • Check that every agreement with third parties that are required to operate the web site are in the organisation's own name. These may include the registration of domain names, SSL certificates, hosting contracts, monitoring services, data feeds, affiliate marketing agreements and service providers such as for address look-up, credit checks and making online payments.
    • ensure the third parties have the organisation's official contact details, and not those of an employee or of the site's developers
    • make note of any renewal dates
  • Obtain a copy of everything required for the web site including scripts, static files, configuration settings, source code, account details and encryption keys. Keep this updated with changes as they are made.
    • verify who legally owns the source code, designs, database, photographs, etc.
    • check what other licences affect the web site (e.g. use of open source and proprietary software libraries, database use limitations).

Do what you can, when you can. Once those are done, then:

  • Verify the web site and all its components (e.g. web widgets and other third party code/content) does not include common web application vulnerabilities that can be exploited by attackers (e.g. SQL injection, cross-site scripting).
  • Check what obligations the organisation is under to protect business and other people's data such as the Data Protection Act, guidance from regulators, trade organisation rules, agreements with customers and other contracts (e.g. PCI DSS via the acquiring bank).
    • impose security standards and obligations on suppliers and partner organisations
    • keep an eye open for changes to business processes that affect data
  • Document (even just some short notes) the steps to rebuild the web site somewhere else, and to transfer all the data and business processes to the new site.
    • include configuration details and information about third-party services required
    • think about what else will need to be done if the web site is unavailable (does it matter, if so what exactly is important?)
  • Provide information to the web site's users how to help protect themselves and their data.
    • point them to relevant help such as from GetSafeOnline, CardWatch and Think U Know
    • provide easy methods for them to contact the organisation if they think there is a security or privacy problem
  • Monitor web site usage behaviour (e.g. click-through rate, session duration, shopping cart abandonment rate, conversion rate), performance (e.g. uptime, response times) and reputation (e.g. malware, phishing, suspicious applications, malicious links) to gather trend data and identify unusual activity.
    • web server logs are a start, but customised logging is better
    • use reputable online tools (some of which are free) to help.

That's just the basics. So, what would be next for an SME? If the web site is a significant sales/engagement channel, the organisation has multiple web sites, is in a more regulated sector or one that is targetted particularly by criminals (e.g. gaming, betting and financial), takes payments or does other electronic commerce, allows users to add their own content or processes data for someone else, the above is just the start. Those SMEs probably need to be more proactive.

This helps to protect the SME's business information, but also helps to protect the web site users and their information. After all, the users are existing and potential customers, clients and citizens.

Oh, the best response I had to someone when I was explaining my work: "You're an anti-hacker than?". Well, I suppose so, but it's not quite how I'd describe it.

Any comments or suggestions?

Posted on: 02 July 2010 at 08:18 hrs

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08 January 2010

What Web Browser Is Being Used?

The web browser (user agent) normally sends a string of text to identify itself, but this can be blank or many other things, and can be altered by users.

Partial screen capture of http://www.botsvsbrowsers.com/category/1/index.html showing some of the Mozilla web browser user agent strings

The Bots vs Browsers (robots versus web browsers) web site monitors the user agent identification strings and helpfully provides access to their valuable data. They have identified over 400,000 different user agent strings to date. You can see 5,000 unidentified that are not obviously any particular search engine robot or browser and could be accidental, mischievous or malicious.

Partial screen capture of http://www.botsvsbrowsers.com/category/0/index.html showing some of the unidentified user agent strings

Always treat user agent strings as untrusted, and check their length and content before using the sanitised text to display, or in decision-making logic or when writing it to a file or database. The lists for particular types of devices (e.g. the iPhone) may be useful to remind you of the range of values sent. User agent strings certainly shouldn't be used for any form of user authentication.

Posted on: 08 January 2010 at 09:18 hrs

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29 December 2009

Adverts and Privacy Notices

The Interactive Advertising Bureau (IAB) and Association of American Advertising Agencies (4A's) have published a draft revised Standard Terms and Conditions for Interactive Advertising. Whilst this is principally aimed at the USA market, due to the international nature of the Internet, I thought it worth a mention here.

Photograph of a shop's SALE banner beside various London souvenirs and other gifts

Use of the template (full title "Standard Terms and Conditions for Interactive Advertising for Media Buys One Year or Less") is voluntary and open to negotiation between media companies and advertisers. However it does discuss data usage and privacy. This is important if you have advertising on your own web site and need to write a privacy notice. Without knowing the agreement between the advertiser and media company, how can you inform your web site users what will happen to their personal information? Although this is only an example template, it probably contains most of the likely issues you will come across in other ones. The definitions of "user volunteered data", "performance data", "site data" and "use of collected data" probably need careful reading and advice from a lawyer! The education version provides some further explanation of terminology and the changes since the previous version.

The template also describes the "special situation of User-Generated Content (UGC) pages" on advert placement and positioning—there could be an interesting discussion if the actual content was neither that intended by the site owner, nor that added by the user, but instead was the result of some malicious injection.

There doesn't seem to be any reference to malware on the site or malware delivered by the advert.

Of course, including third party content is a risk that should be considered in itself.

Posted on: 29 December 2009 at 10:28 hrs

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20 March 2009

Do Apostrophes Receive Too Much Bad Press?

The poor apostrophe gets such bad press. It's implicated in so many SQL Injection problems and now it has been banned by some local councils in the UK.

Yes Birmingham City Council and Wakefield Council have been so concerned about punctuation usage they have banned apostrophes in street names and thus on road signs, according to recent news reports such as in the Daily Mail and Yorkshire Evening Post.

I wasn't able to find confirmation on the councils' own web sites—I was also hoping perhaps the council leader or spokesperson might have had an apostrophe in their own family name. Actually no members from either council have apostrophes, or any other "unusual" characters, in their names. Birmingham's web site search kindly refused to tell me anything about the apostrophe:

Partial screen capture of a Birmingham City Council web page showing the search form containing the word 'apostrophe' and the message 'A problem has occurred with this search.' that appears after submitting the form

This has got many people bothered by the dumbing down, especially those in the Apostrophe Protection Society.

I don't think we'll be able to get away with banning characters in the web application world to prevent issues like SQL injection. Yes there are many web apps that don't allow apostrophes in submitted data rather than tackling the root cause of the weakness. The use of database commands with bound parameters combined with appropriate validation, decoding, encoding and escaping are the answers.

PS It's not just apostrophes (or single quotation marks) you have to worry about.

Posted on: 20 March 2009 at 08:19 hrs

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