On May 19, 2021, a Microsoft blog post announced that “The future of Internet Explorer on Windows 10 is in Microsoft Edge” and that “the Internet Explorer 11 desktop application will be retired and go out of support on June 15, 2022, for certain versions of Windows 10.” According to an associated FAQ page, those “certain versions” include Windows 10 client SKUs and Windows 10 IoT. According to data from Statcounter, Windows 10 currently accounts for over 70% of desktop Windows market share on a global basis, so this “retirement” impacts a significant number of Windows systems around the world.

As the retirement date for Internet Explorer 11 has recently passed, we wanted to explore several related usage trends:

• Is there a visible indication that use is declining in preparation for its retirement?

• Where is Internet Explorer 11 still in the heaviest use?

• How does the use of Internet Explorer 11 compare to previous versions?

• How much Internet Explorer traffic is “likely human” vs. “likely automated”?

• How do Internet Explorer usage patterns compare with those of Microsoft Edge, its replacement?

The long goodbye

Publicly released in January 2020, and automatically rolled out to Windows users starting in June 2020, Chromium-based Microsoft Edge has become the default browser for the Windows platform, intended to replace Internet Explorer. Given the two-year runway, and Microsoft’s May 2021 announcement, we would expect to see Internet Explorer traffic decline over time as users shift to Edge.

Looking at global request traffic to Cloudflare from Internet Explorer versions between January 1 and June 20, 2022, we see in the graph below that peak request volume for Internet Explorer 11 has declined by approximately one-third over that period. The clear weekly usage pattern suggests higher usage in the workplace than at home, and the nominal decline in traffic year-to-date suggests that businesses are not rushing to replace Internet Explorer with Microsoft Edge. However, we expect traffic from Internet Explorer 11 to drop more aggressively as Microsoft rolls out a two-phase plan to redirect users to Microsoft Edge, and then ultimately disable Internet Explorer. Having said that, we do not expect Internet Explorer 11 traffic to ever fully disappear for several reasons, including Microsoft Edge’s “IE Mode” representing itself as Internet Explorer 11, the ongoing usage of Internet Explorer 11 on Windows 8.1 and Windows 7 (which were out of scope for the retirement announcement), and automated (bot) traffic masquerading as Internet Explorer 11.

It is also apparent in the graph above that traffic from earlier versions of Internet Explorer has never fully disappeared. (In fact, we still see several million requests each day from clients purporting to be Internet Explorer 2, which was released in November 1995 — over a quarter-century ago.) After version 11, Internet Explorer 7, first released in October 2006 and last updated in May 2009, generates the next largest volume of requests. Traffic trends for this version have remained relatively consistent. Internet Explorer 9 was the next largest traffic generator through late May, when Internet Explorer 6 seemed to stage a comeback. (Internet Explorer 7 saw a slight bump in traffic at that time as well.)

Where is Internet Explorer 11 used?

Perhaps unsurprisingly, the United States has accounted for the largest volume of Internet Explorer 11 requests year-to-date. Similar to the global observation above, daily peak request traffic has declined by approximately one-third. With request volume approximately one-fourth that seen in the United States, Japan ostensibly has the next largest Internet Explorer 11 user base. (And published reports note that Internet Explorer’s retirement is likely to cause Japan headaches 'for months'” because local businesses and government agencies didn’t take action in the months ahead of the event.)

However, unusual shifts in Brazil’s request volume, seen in the graph above, are particularly surprising. For several weeks in January, Internet Explorer 11 traffic from the country appears to quadruple, with the same behavior seen from early May through mid-June, as well as a significant spike in March. Classifying the request traffic by bot score, as shown in the graph below, makes it clear that the observed increases are the result of automated (bot) traffic presenting itself as coming from Internet Explorer 11.

Further, analyzing this traffic to see what percentage of requests were mitigated by Cloudflare’s Web Application Firewall, we find that the times when the mitigation percentage increased, as shown in the graph below, align very closely with the periods where we observed the higher levels of automated (bot) traffic. This suggests that the spikes in Internet Explorer 11 traffic coming from Brazil that were seen over the last six months were from a botnet presenting itself as that version of the browser.

Bot or not

Building on the Brazil analysis, breaking out the traffic for each version by associated bot score can help us better understand the residual traffic from long-deprecated versions of Internet Explorer shown above. For requests with a bot score that characterizes the traffic as “likely human”, the graph below shows clear weekly traffic patterns for versions 11 and 7, suggesting that the traffic is primarily driven by systems primarily in use on weekdays, likely by business users. For Internet Explorer 7, that traffic pattern becomes more evident starting in mid-February, after a significant decline in associated request volume.

Interestingly, that decline in “likely human” Internet Explorer 7 request volume aligns with an increase in “likely automated” (bot) request volume for that version, visible in the graph below. Given that the “likely human” traffic didn’t appear to migrate to another version of Internet Explorer, the shift may be related to improvements to the machine learning model that powers bot detection that were rolled out in the January/February time frame. It is also interesting to note that “likely automated” request volume for both Internet Explorer 11 and 7 has been extremely similar since mid-March. It is not immediately clear why this is the case.

We can also use this data to understand what percentage of the traffic from a given version of Internet Explorer is likely to be automated (coming from bots). The graph below highlights the ratios for Internet Explorer 11 and 7. For version 11, we can see that the percentage has grown from around 60% at the start of 2022 to around 80% in June. For version 7, it starts the year in the 40% range, and more than doubles to over 80% in February and remains consistent at that level.

However, when we look at firewall mitigated traffic percentages, we don’t see the same clear alignment of trends as was visible for Brazil, as discussed above. In addition, only a fraction of the “likely automated” traffic was mitigated, suggesting that the automated traffic is split between being generated by bots and other non-malicious tools, such as performance testing.

Internet Explorer versions 6 & 9 were also discussed above, with respect to driving the largest volume of requests. However, when we examine the “likely automated” request ratios for these two browsers, we find that most of their traffic appears to be bot-driven. Internet Explorer 6 started 2022 at around 80%, growing to 95% in June. In contrast, Internet Explorer 9 starts the year around 90%, drops to 60% at the end of January, and then gradually increases back to the 75-80% range.

As Internet Explorer 6’s “likely automated” traffic has increased, the fraction of it that was mitigated has increased as well. The small bumps visible in the graph above align with the larger spikes in the graph below, potentially due to brief bursts of bot activity. In contrast, mitigated Internet Explorer 9 traffic has remained relatively consistent, even as its automated request percentage dropped and then gradually increased.

For the oldest, long-deprecated versions of Internet Explorer, automated traffic frequently comprises more than 80% of request volume, reaching 100% on multiple days year-to-date. Mitigated traffic generally amounted to under 30% of request volume, although Internet Explorer 2 frequently increased to the 50% range, spiking as high as 90%.

Edging into the future

As Microsoft stated, “the future of Internet Explorer on Windows 10 is in Microsoft Edge.” Given that, we wanted to understand the usage patterns of Microsoft Edge. Similar to the analysis above, we looked at request volumes for the last ten versions of the browser year-to-date. The graph below clearly illustrates strong enterprise usage of edge, with weekday peaks, and lower traffic on the weekends. In addition, the four-week major release cycle cadence is clearly evident, with a long tail of usage extending across eight weeks due to enterprise customers who need an extended timeline to manage updates.

Having said that, in analyzing the split by bot score for these Edge versions, we note that only around 80% of requests are classified as “likely human” for about eight weeks after a given version is released, after which it gradually tapers to around 60%. The balance is classified as “likely automated”, suggesting that those who develop bots and other automated processes recognize the value in presenting their user agents as the latest version of Microsoft’s web browser. For Edge, there does not appear to be any meaningful correlation between firewall mitigated traffic percentages and “likely automated” traffic percentages or the traffic cycles visible in the graph above.

Conclusion

Analyzing traffic trends from deprecated versions of Internet Explorer brought to mind the “I’m not dead yet” scene from Monty Python and the Holy Grail with these older versions of the browser claiming to still be alive, at least from a traffic perspective. However, categorizing this traffic to better understand the associated bot/human split showed that the majority of Internet Explorer traffic seen by Cloudflare, including for Internet Explorer 11, is apparently not coming from actual browser clients installed on user systems, but rather from bots and other automated processes. For the automated traffic, analysis of firewall mitigation activity shows that the percentage likely coming from malicious bots varies by version.

As Microsoft executes its planned two-phase approach for actively moving users off of Internet Explorer, it will be interesting to see how both request volumes and bot/human splits for the browser change over time – check back later this year for an updated analysis.

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