17. April, 2014
This article contains a good summary of the Heartbleed bug and it’s consequences.
Want to know whether you’re affected? Check sites you use here: filippo.io/Heartbleed/
Note: You will want to check the issue date of the certificate as well. If it was issued before the April 8th, 2014, you may still be vulnerable since an attacker might have stolen the private keys.
22. November, 2013
“HTML5 vs. Security” was a talk given by Thomas Röthlisberger of Compass Security AG which gave a nice overview over some of the security problems that HTML5 brings.
Areas covered by the talk:
Together, those technologies allow remote attackers to scan internal networks, access intranet sites and track users.
For example, if you’re visiting a site while connected to a compromised WLAN access point, an attacker might send you a manifest for this site. The manifest then contains the names of some files which exist on the original site plus additional resources. When you’re back in a safe network, the browser will use the saved files when you visit the site again, making the attack permanent.
Another place to save malicious code is the local storage. Or we can use the local storage to attach a permanent ID to the browser / user.
CORS and WebSockets allow to scan the local network for open ports. With Web Workers, thousands of ports can be scanned in the background. Or you can use the technology to build an ad-hoc botnet to crack passwords.
In some cases, these vulnerabilities are necessary to make the new feature useful. What you need to be aware:
- Decline strange/unexpected requests by your browser
- When you configure your server, make sure you send the correct Access-Control-Allow-Origin headers. Never configure your server to reply with “*”.
- There is no anonymity if you allow web sites access to the Geolocation API or local storage.
17. July, 2013
If you “Back up my data” is enabled on your Android phone, then Google keeps a clear-text, unencrypted copy of your WLAN passwords on its servers. Since Google is an US company, the government and its agencies have access to this data. Google also keeps a database with the location of all WLANs (for their location service) so it’s trivial for them to gain access (even though someone must physically walk/drive into the range of the WLAN router).
Solution: Disable this function, use a local backup program (disable cloud backup for them as well) and change all your passwords.
26. February, 2013
David Blake posted a current overview of Man in the Middle type attacks: 15 Surprising Ways You Could Fall Victim to a Man in the Middle Attack
- Key-loggers (hard- and software)
- Browser plugins
- Cameras (a.k.a Shoulder Surfing)
- Wireless attacks
7. February, 2013
The Common Vulnerabilities and Exposures or CVE is a registry for security related flaws and computer systems.
The old counting system allowed only for 9’999 bugs per year.
That’s no longer enough.
Isn’t that scary?
25. January, 2013
On Wednesday, GitHub improved their code search. A few hours later, a couple of people had tried “begin rsa private key” and got more results than any sane person would anticipate. Just in case, this isn’t a problem of GitHub, the same problem can be found on pastebin or with Google.
There are several reasons for people to publish sensitive data:
- They don’t know what they’re doing (ignorance)
- They are sure “no one will ever find out” (security by obscurity)
- Distributing sensitive data anonymously (crackers)
- It’s easier that way (laziness)
It’s not a corner case, either. The SQL*Plus tool from Oracle has no easy way to set the password from a script except by passing it on the command line which effectively publishes the password to any user on the same computer. You can install a “client-side Oracle wallet” to fix this.
But the common issue behind all that is that it’s either too easy to do it wrong or too hard to do it right. Just to see how bad the situation is, I asked for a secure web login/example on stackoverflow.com. The answer was basically “it’s too complex to do.”
26. September, 2012
In the past few weeks, I started getting mails from friends which just contain a link:
9/25/2012 12:34:56 PM
Turns out that someone is analyzing my Facebook account and sends me mails using names from my friends list.
If you get such a mail, don’t click on the link. It probably points to a page which infects your computer with a virus.
Right now, these mails are pretty easy to identify as fake because the email address is wrong. But you should know that the sender address in emails is just a text; neither the sending nor the receiving computer will check what is in there. A spammer can write anything into that field. If the scheme starts to fail too often, I expect to see “better” email addresses.
This means as a receiver, you should never click on links in emails. As a sender, you should never share links by email.