Security Basics mailing list archives
RE: FUD - was FAX a virus
From: "Craig Wright" <cwright () bdosyd com au>
Date: Tue, 6 Mar 2007 09:02:18 +1100
Scott has stated - "Is that a risk? You can determine that by evaluating how the Windows process operates. I'm assuming it's a service on your box. You will want that service to launch with an unprivileged user account, not the local system account." This is not a risk. This is a possible vulnerability. A risk is the chance that a threat will exploit a vulnerability. Thus again as was stated, this needs to be a risk based response. The threat needs to be considered. The impact needs to be taken into account. Scott, Yes, as you state you are making assumptions. You also fail to read the emails. Assumptions are dangerous and it is always better to clear the issue and not make assumptions. Regards, Craig -----Original Message----- From: Scott Ramsdell [mailto:Scott.Ramsdell () cellnet com] Sent: Tuesday, 6 March 2007 3:34 AM To: Scott Ramsdell; Craig Wright; security-basics () securityfocus com Cc: alcides.hercules () gmail com; wesley () mcgrewsecurity com Subject: RE: FUD - was FAX a virus Alcides, Alcides, I would like to take the time to address your concern more fully.
From your original email (which didn't seem to warrant inclusion below
Craig's tirade which he appears to have been simultaneously writing and ignoring), I'll sum up what some of us interpreted as your environment. You receive faxes that you want to extract information from. You have a process that uses OCR (you didn't mention this but I'm making the assumption) to identify interesting fields in the fax, and you then read those fields into your system for processing. When you identify a field and read it, you are going to want for your system to validate the input. So, in a name field, ensure that only valid characters are accepted. If you have a field that requires special characters, such as the parenthesis or dashes in a phone number field, you will want to take care that only those special characters are allowed through. If you allow forward slashes and periods through for instance, you run the risk of passing http://my.bad.code to your Windows service. If you allow the asterisk and parenthesis through, you run the risk of allowing SQL injection passed to your service. Is that a risk? You can determine that by evaluating how the Windows process operates. I'm assuming it's a service on your box. You will want that service to launch with an unprivileged user account, not the local system account. If your process stores the information you extract (likely), it may store the info in a SQL database. That is where the concern would be that your front end service is passing a ("an" if you want) SQL command to your back end server. Is that a concern? The communication is one-way as Craig so eloquently pointed out. But what if the command is to drop a database? In that case there was never any intention of receiving data back, it's a malicious vandalism of your database. Yes, you do have concerns. You should shoot the Pen Test list an email with specific info on what your process extracts, how it identifies interesting fields, how it runs on your box, and how it stores the results. Likely you are not the first person doing what you're doing, and likely someone on the Pen Test list has seen something similar. If not, they will at least be able to offer more advice, tailored to your specific situation. I'm through with this thread, somehow being called unprofessional is a turn off. Kind Regards to most, Scott Ramsdell -----Original Message----- From: Scott Ramsdell Sent: Monday, March 05, 2007 8:12 AM To: 'Craig Wright'; security-basics () securityfocus com Cc: alcides.hercules () gmail com; wesley () mcgrewsecurity com Subject: RE: FUD - was FAX a virus Craig, You don't get it. The concerns expressed weren't regarding the method of transmission. The concerns were with respect to the Windows service that accepts the input.
From what Alcides says, he has a fax server (this will convert from
analog to digital, BTW) and he has a process running on a Windows box that accepts input from the fax server. I merely cautioned him about properly sanitizing the input from the fax server to the Windows service! Very valid concern. Alcides, shoot your question over to the Pen Test list, that way you'll get a technical response rather than a reply from a lawyer. Kind Regards, Scott Ramsdell -----Original Message----- From: Craig Wright [mailto:cwright () bdosyd com au] Sent: Friday, March 02, 2007 3:11 PM To: security-basics () securityfocus com Cc: alcides.hercules () gmail com; Scott Ramsdell; wesley () mcgrewsecurity com Subject: FUD - was FAX a virus Hello, The idea of faxing a virus is ludicrous and this demonstrates the FUD in the industry. I have to state that I am amazed that people here are even considering this seriously! In other words, that people are willing to comment on a technology with no idea how it works without even taking the time to check the facts. This is one of the systemic faults within the security industry at the moment. The initial question was Ok. It demonstrates that the person wanted to learn. The responses demonstrate that people are willing to open their mouth without first checking the facts. This is a bad thing - please understand this. A Facsimile is an analogue device - it does not send digital information and it can not even send the same information twice. Not EVER! More on this later. Some history seeing as a lesson seems to be needed. (Responding without checking facts - bah - as you can see this is a pet hate, people in security need to take the time to LEARN the truth and not make FUD). History of the Fax. (A very condensed version) Alexander Bain (1818-1903) In 1843 invented a precursor that used two pens connected by an electrical wire to send information. In 1862 (correct me if this date is wrong) Giovanni Caselli made the first pantelegraph to electronically send photos. ? On date, but about 1880. Elisha Gray (founder of the Western Electric Company) patented a simple (though it took a room to hold and oft caught on fire) a facsimile transmission system. Arthur Korn (1870-1945) sent the first inter-city fax in 1907 using a "telephotographer" to send photos from Munich to Berlin. And so it goes till Xerox got into the picture in 1964 with Long Distance Xerography (LDX) and shortly after with the Magnafax Telecopier (weighing only 46-pound) in 1966. This was where we have what is essentially a "modern" facsimile machine. How does a Fax machine work? (First faxes in general than computers) A fax is a scan of a block of the image to be sent. The scan is analogue in that the intensity of the tone is converted to a digital signal. This scan is impacted by ambient temperature, lighting conditions and many other factors - although none of these will make any difference that the human eye can note. This signal is sent as an electronic wave function. Again, analogue and not digital. It is converted (taking phone line faxes and excluding radio fax in this case) as a signal similar to a modem communication that is transmitted to a sound wave if you listen to this on a phone. Line conditions always impact the transmission. A white noise function creates variations in the wave form that reflects the error rate on the page. In a computer fax card or program, this is interpreted and converted to make the digital image. The image varies each and ever time that a fax is send and it is not possible for the sender to control all conditions to ensure that any stream of information comes out the same. If you do not believe this statement I have to have you read up on Quantum cromodynamics, and Quantum wave physics and Uncertainty. (This is a topic best off list for any of you who want to chat more on a very interesting subject). Basically, this is a probabilistic function. If for a SPECIFIC card in a SPECIFIC computer a SPECIFIC set of code could be send to that machine that could case some unknown fault (let alone a virus), the sender needs also to be able to control the line between the receive and him/herself. Probabilistically we are talking a 1 in 10^34 or larger chance of being able to control all these conditions EVEN if there was a specific piece of code (which has never been shown to exist or even be feasible) of controlling all the required conditions. There is a larger probability that all the electrons and quarks in both your body and those of the wall will somehow align just as you walk into the wall - allowing you to pass through it as it the wall was not there. So to reiterate (to the tune of Monty Python's SPAM). FUD, FUD, FUDity FUD.... Now, to the real issue. (Yes time to get on my soapbox AGAIN). Security "professionals" do not make FUD. Security "professionals" do not propagate FUD. Security "professionals" check the facts BEFORE going off half cocked with a story that is about as likely as an alien abductions. Please check the facts before damaging the industry as a whole. I do say industry as a whole for this. Each time we state something that is not scientific and has no basis in fact designed to make other percieve an exagerated sense of risk associated with a theretical conditiuon, we make FUD. In doing this, we lower the standing of all "security professionals." To even state - "the threat is extraordinarily low" is an exageration. If all worlds possible in all galaxies in the known universe all have all their people sending faxes for all the life of the universe, than the chance of sending information in the manner suggested is still approximately zero. This is even with modern error correction techniques. So to even make this an issue is FUD. Risk first needs a threat, a threat needs an impact and a probabilistic likelihood. If these are all close to zero, than the risk is zero. Facts first - facts second and than make the decision based on reality. FUD and an exageration of risk is one of the greatest evils today. Please do not jump on this bandwagon! Please let's start acting like Security "professionals". Regards, Craig S Wright PS FUD = bad - please remember, FUD = bad... Liability limited by a scheme approved under Professional Standards Legislation in respect of matters arising within those States and Territories of Australia where such legislation exists. DISCLAIMER The information contained in this email and any attachments is confidential. If you are not the intended recipient, you must not use or disclose the information. If you have received this email in error, please inform us promptly by reply email or by telephoning +61 2 9286 5555. Please delete the email and destroy any printed copy. Any views expressed in this message are those of the individual sender. You may not rely on this message as advice unless it has been electronically signed by a Partner of BDO or it is subsequently confirmed by letter or fax signed by a Partner of BDO. BDO accepts no liability for any damage caused by this email or its attachments due to viruses, interference, interception, corruption or unauthorised access. Liability limited by a scheme approved under Professional Standards Legislation in respect of matters arising within those States and Territories of Australia where such legislation exists. DISCLAIMER The information contained in this email and any attachments is confidential. If you are not the intended recipient, you must not use or disclose the information. If you have received this email in error, please inform us promptly by reply email or by telephoning +61 2 9286 5555. Please delete the email and destroy any printed copy. Any views expressed in this message are those of the individual sender. You may not rely on this message as advice unless it has been electronically signed by a Partner of BDO or it is subsequently confirmed by letter or fax signed by a Partner of BDO. BDO accepts no liability for any damage caused by this email or its attachments due to viruses, interference, interception, corruption or unauthorised access.
Current thread:
- RE: FUD - was FAX a virus Craig Wright (Mar 06)
- <Possible follow-ups>
- FUD - was FAX a virus Craig Wright (Mar 06)
- Re: FUD - was FAX a virus Robert Wesley McGrew (Mar 06)
- RE: FUD - was FAX a virus Craig Wright (Mar 06)
- RE: FUD - was FAX a virus Scott Ramsdell (Mar 06)
- RE: FUD - was FAX a virus Scott Ramsdell (Mar 06)
- Re: FUD - was FAX a virus TheGesus (Mar 06)
- Re: FUD - was FAX a virus Robert Wesley McGrew (Mar 06)
- RE: FUD - was FAX a virus Craig Wright (Mar 06)
- RE: FUD - was FAX a virus Craig Wright (Mar 06)
- Re: FUD - was FAX a virus Robert Wesley McGrew (Mar 07)
- RE: FUD - was FAX a virus Peter Denyer (Mar 07)
- Re: FUD - was FAX a virus Robert Wesley McGrew (Mar 07)
- RE: FUD - was FAX a virus Bob Radvanovsky (Mar 06)
- RE: FUD - was FAX a virus Craig Wright (Mar 07)
- RE: FUD - was FAX a virus Craig Wright (Mar 07)
- Re: FUD - was FAX a virus Robert Wesley McGrew (Mar 07)
- Re: RE: FUD - was FAX a virus krymson (Mar 07)
- RE: RE: FUD - was FAX a virus Craig Wright (Mar 07)