Exploits for Adobe Vulnerabilities Spiked in 2018

Malware authors weaponized more Adobe software vulnerabilities in 2018 than any previous year while the actual number of newly disclosed security flaws in the company's products dropped significantly since reaching an all-time-high in 2016.

Security vendor RiskSense recently analyzed over 20 years of Adobe vulnerability data gathered from Adobe's own security bulletins and numerous third-party sources, including bug bounty programs and the national vulnerability database.

The analysis showed that of the 374 new Adobe vulnerabilities disclosed in 2018, exploits or malware became available for 177—or 47%—of them. Fifty of the vulnerabilities were weaponized even before a patch was available.

The numbers are significantly higher than previous years both in terms of the percentage of new vulnerabilities that were weaponized, and in terms of the number of Adobe flaws that were exploitable before patch availability. In 2017, for instance, just 21% of the vulnerabilities disclosed had associated exploits and malware. Similarly, the rate of exploits in the wild before patch availability was some three times higher last year than the previous high set in 2010, RiskSense said.

Ironically, the increased and accelerated weaponization of Adobe vulnerabilities happened during a year in which the overall number of new vulnerabilities disclosed was 31% lower than the record 538 vulnerabilities reported in 2016.

"2018 was definitely exceptional in terms of the weaponization of [Adobe] vulnerabilities," says Anand Paturi, manager of product research for RiskSense. What's not clear is whether the numbers are an anomaly or are indicative of a new trend, he says.

Paturi says that while malware authors were responsible for weaponizing some vulnerabilities, security researchers contributed to the situation as well by releasing proof-of-exploit code for Adobe flaws, sometimes before patch availability.  

"While this code is often very important for helping to understand the vulnerability and demonstrate its severity, this information can also sometimes accelerate the development of threats by attackers," Paturi says.

Acrobat Reader, Flash Player Most Vunlerable

RiskSense's study found that a total of 2,891 vulnerabilities were reported in Adobe products between 1996 and the end of 2018—a vast majority of them in Acrobat Reader and Flash Player. Reader accounted for 1,338 vulnerabilities, while Flash Player had 1,083.

Adobe's cloud-hosted Acrobat DC was another big contributor to the overall vulnerability count, with 300 since the product's 2015 launch. Nearly four-in-ten (38%) of the reported vulnerabilities in Adobe's products over the past 20 years were buffer overflows.

Exploits and malware are currently available for 721 of the vulnerabilities, of which 152 are either remotely exploitable, enable privilege escalation, or are associated with Web apps.

Security experts in recent years have considered Flash Player in particular as a major security threat because of the number of vulnerabilities—including numerous zero-days—that have been discovered in the product over the years. Attackers have frequently exploited Flash vulnerabilities to attack users across multiple platforms, and exploits for these flaws have been a staple in exploit kits such as Neutrino and Angler for years.

However, Adobe's decision to kill off Flash Player by 2020 has resulted in an overall decline in attacker interest in the technology - and a renewed focus on Acrobat Reader instead, Paturi says. Last year, there were just 24 reported Flash Player vulnerabilities.

This was a result of both Flash Player becoming less popular and of browser vendors adding security improvements to address Flash-related threats. "This has shifted attention to Adobe Acrobat Reader," Paturi note. "As the browser-based exploits of Flash have dried up, attackers are having to work a bit harder and are shifting attention back to attacking Reader," he says.

"Specifically, we are seeing a spike in remote code execution (RCE) exploits in Acrobat Reader and we expect to see that continue to rise."

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