Blogs. DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization) have proven themselves to be important and effective countermeasures against the types of exploits that we see in the wild today. Of course, any useful mitigation technology will attract scrutiny, and over the past year there has been an increasing amount of research and discussion on the subject of bypassing DEP and ASLR [1,2]. In this blog post we wanted to spend some time discussing the effectiveness of these mitigations by providing some context for the bypass techniques that have been outlined in attack research. The key points that should be taken away from this blog post are: DEP and ASLR are designed to increase an attacker's exploit development costs and decrease their return on investment.The combination of DEP and ASLR is very effective at breaking the types of exploits we see in the wild today, but there are circumstances where they can both be bypassed.
For enterprises and users For ISVs References. OWASP. XSS Filter Evasion Cheat Sheet. Last revision (mm/dd/yy): 07/4/2018 This cheat sheet lists a series of XSS attacks that can be used to bypass certain XSS defensive filters. Please note that input filtering is an incomplete defense for XSS which these tests can be used to illustrate. Basic XSS Test Without Filter Evasion This is a normal XSS JavaScript injection, and most likely to get caught but I suggest trying it first (the quotes are not required in any modern browser so they are omitted here): XSS Locator (Polygot) The following is a "polygot test XSS payload.
" javascript:/*--></title></style></textarea></script></xmp><svg/onload='+/"/+/onmouseover=1/+/[*/[]/+alert(1)//'> Image XSS using the JavaScript directive Image XSS using the JavaScript directive (IE7.0 doesn't support the JavaScript directive in context of an image, but it does in other contexts, but the following show the principles that would work in other tags as well: No quotes and no semicolon Case insensitive XSS attack vector HTML entities Malformed A tags <! <! XSS (Cross Site Scripting) Cheat Sheet.
APT. RootKit Recovery. Farlight.org. Boffins ‘crack’ HTTPS encryption in Lucky Thirteen attack. The security of online transactions is again in the spotlight as a pair of UK cryptographers take aim at TLS. TLS, or Transport Layer Security, is the successor to SSL, or Secure Sockets Layer. It's the system that puts the S into HTTPS (that's the padlock you see on secure websites), and provides the security for many other protocols, too. Like 2011's infamous BEAST attack, it has a groovy name: Lucky Thirteen. The name comes from the fact that encrypted TLS packets have thirteen header bytes that are consumed in one of the cryptographic calculations on which TLS relies. → The paper's name is a bit cheeky - the authors wryly note that "in some sense, thirteen is lucky, but twelve would have been luckier," since 12-byte headers would make their attack even more efficient. To give you some idea of what makes cryptographers tick, and how they manage to extract order even out of carefully-contrived chaos, here's how it all started.
The AES block cipher encrypts 16 bytes at a time. IPv6 Insecurity. Tor and the BEAST SSL attack. Today, Juliano Rizzo and Thai Duong presented a new attack on TLS <= 1.0 at the Ekoparty security conference in Buenos Aires. Let's talk about how it works, and how it relates to the Tor protocol. Short version: Don't panic. The Tor software itself is just fine, and the free-software browser vendors look like they're responding well and quickly. I'll be talking about why Tor is fine; I'll bet that the TBB folks will have more to say about browsers sometime soon. There is some discussion of the attack and responses to it out there already, written by seriously smart cryptographers and high-test browser security people. So I'll do my best.
Thanks to the authors of the paper for letting me read it and show it to other Tor devs. The attack How the attack works: Basic background This writeup assumes that you know a little bit of computer stuff, and you know how xor works. Let's talk about block ciphers, for starters. Okay, so nobody reasonable uses ECB. Here's why that's bad. Whoops! Nope.