Our researchers have discovered a new zero-day exploit in Adobe Flash used in malvertisement attacks. The exploit affects the most recent version of Adobe Flash, and is now identified as CVE-2015-0313. Our initial analysis suggests that this might have been executed through the use of the Angler Exploit Kit, due to similarities in obfuscation techniques and infection chains.
According to our data, visitors of the popular site dailymotion.com were redirected to a series of sites that eventually led to the URL hxxp://www.retilio.com/skillt.swf, where the exploit itself was hosted. It is important to note that infection happens automatically, since advertisements are designed to load once a user visits a site. It is likely that this was not limited to the Dailymotion website alone, since the infection was triggered from the advertising platform and not the website content itself. Trend Micro detects this exploit as SWF_EXPLOIT.MJST and blocks the URL mentioned above. The ads from this particular infection chain appear to be down as of this writing.
We have been monitoring this attack since January 14, and saw a spike in the hits to the IP related to the malicious URL around January 27. According to data from the Trend Micro™ Smart Protection Network™, most of the users who accessed the malicious server related to the attack are from the United States.
Figure 1. Number of accessed counts to one of the affected IP addresses
This post serves to warn end-users and enterprises of the severity of this threat. So far we’ve seen around 3,294 hits related to the exploit, and with an attack already seen in the wild, it’s likely there are other attacks leveraging this zero-day, posing a great risk of system compromise to unprotected systems. Since the exploit affects the latest version of Flash, 188.8.131.526, users may consider disabling Flash Player until a fixed version is released. Adobe has confirmed that this is a zero-day exploit and the patch is expected to be available this week to address this. More details can be found in this advisory Adobe released for this vulnerability.
The existing Sandbox with Script Analyzer engine, which is part of Trend Micro™ Deep Discovery, can also be used to detect this threat by its behavior without any engine or pattern update. The Browser Exploit Prevention feature in our endpoint products such as Trend Micro™ Security, OfficeScan, and Worry-Free Business Security blocks the exploit once the user accesses the URL it is hosted in. Browser Exploit Prevention also protects against exploits that target browsers or related plugins.
This is only the latest of the zero-day vulnerabilities found in Adobe Flash this month. Just weeks ago, we wrote a couple of blog entries (Flash Greets 2015 With New Zero-Day, Analyzing CVE-2015-0311: Flash Zero Day Vulnerability) pertaining to zero-day vulnerabilities found in Adobe Flash Player and covered under CVE-2015-0311.
This is a developing story and we will continue to update this entry as new information and development about this threat surfaces. We will also share the technical analysis once the Adobe Flash update is released.
With additional analysis from Joseph C. Chen
Update as of February 2, 2015, 8:07 AM PST
Trend Micro™ Deep Security and Vulnerability Protection (formerly the Defense Firewall plug-in for OfficeScan) protects user systems from threats that may leverage this zero-day vulnerability following the DPI rule:
- 1006468 – Adobe Flash Player Unspecified Vulnerability (CVE-2015-0313)
Update as of February 3, 2015, 11:49 AM PST
We have updated information on the exploit kit used in this attack. We now believe it is not Angler, but the Hanjuan Exploit Kit. More details in our blog entry A Closer Look at the Exploit Kit in CVE-2015-0313 Attack.