Cisco Blogs


Cisco Blog > Security

Cross-Site Request Forgery Attacks and Mitigations

Cross-Site Request Forgery (CSRF) attacks: there are already enough articles out there that can explain what a CSRF attack is and provide potential examples. There are also plenty of security alerts that have been released by various vendors whose products are affected by CSRF-related vulnerabilities.

CSRF attacks usually target web applications and attempt to make unwanted changes on server data or extract sensitive information from a web application. Attackers do this by luring an authenticated user into making a specially crafted web request. It’s important, regardless of role, for everyone to have a basic understanding of CSRF attacks and the available options to protect against them.

For more information about basic CSRF concepts and potential mitigations, see our new Applied Mitigation Bulletin Understanding Cross-Site Request Forgery Threat Vectors. Although this document does not attempt to provide all the technical details associated with CSRF, it does aim to summarize the CSRF technique and provide methods that can be potentially used by developers, network administrators and users to protect against CSRF attacks.

For all things related to Security don’t forget to visit the Cisco Security Intelligence Operations (SIO) Portal—the primary outlet for Cisco’s security intelligence and the public home to all of our security-related content. Just go to cisco.com/security.

Tags: , , , , , ,

Apache Darkleech Compromises

Dan Goodin, editor at Ars Technica, has been tracking and compiling info on an elusive series of website compromises that could be impacting tens of thousands of otherwise perfectly legitimate sites. While various researchers have reported various segments of the attacks, until Dan’s article, no one had connected the dots and linked them all together.

Dubbed “Darkleech,” thousands of Web servers across the globe running Apache 2.2.2 and above are infected with an SSHD backdoor that allows remote attackers to upload and configure malicious Apache modules. These modules are then used to turn hosted sites into attack sites, dynamically injecting iframes in real-time, only at the moment of visit.

Because the iframes are dynamically injected only when the pages are accessed, this makes discovery and remediation particularly difficult. Further, the attackers employ a sophisticated array of conditional criteria to avoid detection:

  • Checking IP addresses and blacklisting security researchers, site owners, and the compromised hosting providers;
  • Checking User Agents to target specific operating systems (to date, Windows systems);
  • Blacklisting search engine spiders;
  • Checking cookies to “wait list” recent visitors;
  • Checking referrer URLs to ensure visitor is coming in via valid search engine results. Read More »

Tags: , , , , , ,

March Madness May Equal to Malware Madness

March 29, 2013 at 8:05 am PST

basketball1Are you excited about March Madness? Turn on a TV and it will be hard to avoid the games, the news, the commentaries, and the jokes about it. If you eavesdrop in any restaurant, bar, or office conversation, I can assure you that you will hear something about it. Even U.S. President Barack Obama filled out a March Madness bracket. Productivity in many offices drops significantly as employees search and watch videos to see how their bracket picks are progressing. At Cisco, we have an open policy and employees can watch and search the scores of their favorite teams. Watch this video posted by CNN where Kip Compton, Cisco’s Video Collaboration Group CTO, talks about March Madness.

During the last couple of years, the industry saw a spike in web malware during the March Madness season. SQL injection attacks, iframe injections, JavaScript, and Java malware were some of the most prevalent. A few months ago, I provided details about some of today’s cyber-criminal tools— exploit kits—and some of the weapons of choice like Blackhole, RedKit, Styx, CrimeBoss, and Cool.

A few things to keep in mind:

  • Legitimate business sites may have vulnerabilities that allow a hostile site to deliver malware.
  • In most drive-by downloads, the victim is willing to dismissively click pop-ups and warnings as they navigate to the desired content. In this case, users may just click on pop-ups or ads to watch videos about their favorite team.
  • Most drive-by downloads can be prevented by keeping software up to date. Read More »

Tags: , , , , , , , ,

Chronology of a DDoS: SpamHaus

Around 12:00 GMT March 16, 2013, a distributed denial of service (DDoS) attack took offline both the spamhaus.org website and a portion of its e-mail services. SpamHaus was able to restore connectivity by March 18; however, SpamHaus is still weathering a massive, ongoing DDoS attack. The DDoS attacks have also had less severe but measurable consequences for the Composite Block List (CBL) as well as Project Honey Pot.

The attackers appear to have hijacked at least one of SpamHaus’ IP addresses via a maliciously announced BGP route and subsequently used a Domain Name System (DNS) server at the IP to return a positive result for every SpamHaus Domain Name System-based Block List (DNSBL) query. This caused all SpamHaus customers querying the rogue nameserver to erroneously drop good connections.

According to the New York Times, Sven Olaf Kamphuis is acting as a “spokesman for the attackers.” Kamphuis is allegedly associated with hosting provider “the CyberBunker,” which is housed in an old, five-story NATO bunker located in the Netherlands. CyberBunker has a reputation for “bulletproof hosting,” not only because of the physically fortified infrastructure, but also for their permissive terms of use, stating “Customers are allowed to host any content they like, except child porn and anything related to terrorism. Everything else is fine.” Kamphuis is also allegedly affiliated with the StopHaus group, which publicly claimed responsibility for the BGP hijack attack via Twitter.  Read More »

Tags: , , , , , , ,

Thoughts on DarkSeoul: Data Sharing and Targeted Attackers

The attacks against South Korean media and banking organizations last week severely disrupted a handful of organizations with a coordinated distribution of “wiper” malware designed to destroy data on hard drives and render them unbootable. At 14:00 KST on March 20, 2013, the wiper was triggered across three media organizations and four banks, setting off a firestorm of speculation and finger-pointing and that which continues as of this writing. In this post, I’ll share a perspective no one else seems to be talking about, but may be the real motivation behind these attacks.

The What and the Possible Why

Let’s start with what we know:

  • The attack was highly targeted
  • The malware was specifically designed to distribute the wiper payload throughout the impacted organizations
  • The malware was timed to deploy its destructive payload simultaneously across all affected organizations
  • The resulting loss of data and downtime has been severe

While the “what” of the attack is well established, the “why” and “how” are still a matter of debate. Theories postulated include an outright act of warfare from North Korea designed to economically disrupt South Korea, or an act of sabotage to cover the tracks of data exfiltration allegedly wrought by China. But what if there were an explanation that was less about countries and politics and more about that all-time motivator of crime: money? Consider, if you will, the following timeline. Read More »

Tags: , , , , , , ,