You're browsing your inbox and spot an email that looks like it's from a brand you trust. Yet, something feels off. This might be a phishing attempt, a common tactic where cybercriminals impersonate reputable entities — we've written about the top 50 most impersonated brands used in phishing attacks. One factor that can be used to help evaluate the email's legitimacy is its Top-Level Domain (TLD) — the part of the email address that comes after the dot.

In this analysis, we focus on the TLDs responsible for a significant share of malicious or spam emails since January 2023. For the purposes of this blog post, we are considering malicious email messages to be equivalent to phishing attempts. With an average of 9% of 2023's emails processed by Cloudflare’s Cloud Email Security service marked as spam and 3% as malicious, rising to 4% by year-end, we aim to identify trends and signal which TLDs have become more dubious over time. Keep in mind that our measurements represent where we observe data across the email delivery flow. In some cases, we may be observing after initial filtering has taken place, at a point where missed classifications are likely to cause more damage. This information derived from this analysis could serve as a guide for Internet users, corporations, and geeks like us, searching for clues, as Internet detectives, in identifying potential threats. To make this data readily accessible, Cloudflare Radar, our tool for Internet insights, now includes a new section dedicated to email security trends.

Cyber attacks often leverage the guise of authenticity, a tactic Cloudflare thwarted following a phishing scheme similar to the one that compromised Twilio in 2022. The US Cybersecurity and Infrastructure Security Agency (CISA) notes that 90% of cyber attacks start with phishing, and fabricating trust is a key component of successful malicious attacks. We see there are two forms of authenticity that attackers can choose to leverage when crafting phishing messages, visual and organizational. Attacks that leverage visual authenticity rely on attackers using branding elements, like logos or images, to build credibility. Organizationally authentic campaigns rely on attackers using previously established relationships and business dynamics to establish trust and be successful.

Our findings from 2023 reveal that recently introduced generic TLDs (gTLDs), including several linked to the beauty industry, are predominantly used both for spam and malicious attacks. These TLDs, such as .uno, .sbs, and .beauty, all introduced since 2014, have seen over 95% of their emails flagged as spam or malicious. Also, it's important to note that in terms of volume, “.com” accounts for 67% of all spam and malicious emails (more on that below).

TLDs

2023 Spam %

2023 Malicious %

2023 Spam + malicious %

TLD creation

.uno

62%

37%

99%

2014

.sbs

64%

35%

98%

2021

.best

68%

29%

97%

2014

.beauty

77%

20%

97%

2021

.top

74%

23%

97%

2014

.hair

78%

18%

97%

2021

.monster

80%

17%

96%

2019

.cyou

34%

62%

96%

2020

.wiki

69%

26%

95%

2014

.makeup

32%

63%

95%

2021

Email and Top-Level Domains history

In 1971, Ray Tomlinson sent the first networked email over ARPANET, using the @ character in the address. Five decades later, email remains relevant but also a key entry point for attackers.

Before the advent of the World Wide Web, email standardization and growth in the 1980s, especially within academia and military communities, led to interoperability. Fast forward 40 years, and this interoperability is once again a hot topic, with platforms like Threads, Mastodon, and other social media services aiming for the open communication that Jack Dorsey envisioned for Twitter. So, in 2024, it's clear that social media, messaging apps like Slack, Teams, Google Chat, and others haven't killed email, just as “video didn’t kill the radio star.”

The structure of a domain name.

The domain name system, managed by ICANN, encompasses a variety of TLDs, from the classic “.com” (1985) to the newer generic options. There are also the country-specific (ccTLDs), where the Internet Assigned Numbers Authority (IANA) is responsible for determining an appropriate trustee for each ccTLD. An extensive 2014 expansion by ICANN was designed to "increase competition and choice in the domain name space," introducing numerous new options for specific professional, business, and informational purposes, which in turn, also opened up new possibilities for phishing attempts.

3.4 billion unwanted emails

Cloudflare’s Cloud Email Security service is helping protect our customers, and that also comes with insights. In 2022, Cloudflare blocked 2.4 billion unwanted emails, and in 2023 that number rose to over 3.4 billion unwanted emails, 26% of all messages processed. This total includes spam, malicious, and "bulk" (practice of sending a single email message, unsolicited or solicited, to a large number of recipients simultaneously) emails. That means an average of 9.3 million per day, 6500 per minute, 108 per second.

Bear in mind that new customers also make the numbers grow — in this case, driving a 42% increase in unwanted emails from 2022 to 2023. But this gives a sense of scale in this email area. Those unwanted emails can include malicious attacks that are difficult to detect, becoming more frequent, and can have devastating consequences for individuals and businesses that fall victim to them. Below, we’ll give more details on email threats, where malicious messages account for almost 3% of emails averaged across all of 2023 and it shows a growth tendency during the year, with higher percentages in the last months of the year. Let's take a closer look.

Top phishing TLDs (and types of TLDs)

First, let’s start with an 2023 overview of top level domains with a high percentage of spam and malicious messages. Despite excluding TLDs with fewer than 20,000 emails, our analysis covers unwanted emails considered to be spam and malicious from more than 350 different TLDs (and yes, there are many more).

A quick overview highlights the TLDs with the highest rates of spam and malicious attacks as a proportion of their outbound email, those with the largest volume share of spam or malicious emails, and those with the highest rates of just-malicious and just-spam TLD senders. It reveals that newer TLDs, especially those associated with the beauty industry (generally available since 2021 and serving a booming industry), have the highest rates as a proportion of their emails. However, it's relevant to recognize that “.com” accounts for 67% of all spam and malicious emails. Malicious emails often originate from recently created generic TLDs like “.bar”, “.makeup”, or “.cyou”, as well as certain country-code TLDs (ccTLDs) employed beyond their geographical implications.

Highest % of spam and malicious emails

Volume share
of spam + malicious 

Highest % of malicious 

Highest % of spam

TLD

Spam + mal %

TLD

Spam + mal %

TLD

Malicious %

TLD

Spam %

.uno

99%

.com

67%

.bar

70%

.autos

93%

.sbs

98%

.shop

5%

.makeup

63%

.today

92%

.best

97%

.net

4%

.cyou

62%

.directory

91%

.beauty

97%

.no

3%

.ml

56%

.boats

87%

.top

97%

.org

2%

.tattoo

54%

.center

85%

.hair

97%

.ru

1%

.om

47%

.monster

80%

.monster

96%

.jp

1%

.cfd

46%

.lol

79%

.cyou

96%

.click

1%

.skin

39%

.hair

78%

.wiki

95%

.beauty

1%

.uno

37%

.shop

78%

.makeup

95%

.cn

1%

.pw

37%

.beauty

77%

Focusing on volume share, “.com” dominates the spam + malicious list at 67%, and is joined in the top 3 by another “classic” gTLD, “.net”, at 4%. They also lead by volume when we look separately at the malicious (68% of all malicious emails are “.com” and “.net”) and spam (71%) categories, as shown below. All of the generic TLDs introduced since 2014 represent 13.4% of spam and malicious and over 14% of only malicious emails. These new TLDs (most of them are only available since 2016) are notable sources of both spam and malicious messages. Meanwhile, country-code TLDs contribute to more than 12% of both categories of unwanted emails.

This breakdown highlights the critical role of both established and new generic TLDs, which surpass older ccTLDs in terms of malicious emails, pointing to the changing dynamics of email-based threats.

Type of TLDs

Spam

Malicious 

Spam + malicious

ccTLDs

13%

12%

12%

.com and .net only

71%

68%

71%

new gTLDs 

13%

14%

13.4%

That said, “.shop” deserves a highlight of its own. The TLD, which has been available since 2016, is #2 by volume of spam and malicious emails, accounting for 5% of all of those emails. It also represents, when we separate those two categories, 5% of all malicious emails, and 5% of all spam emails. As we’re going to see below, its influence is growing.

Full 2023 top 50 spam & malicious TLDs list

For a more detailed perspective, below we present the top 50 TLDs with the highest percentages of spam and malicious emails during 2023. We also include a breakdown of those two categories.

It’s noticeable that even outside the top 10, other recent generic TLDs are also higher in the ranking, such as “.autos” (the #1 in the spam list), “.today”, “.bid” or “.cam”. TLDs that seem to promise entertainment or fun or are just leisure or recreational related (including “.fun” itself), occupy a position in our top 50 ranking.

2023 Top 50 spam & malicious TLDs (by highest %)

Rank

TLD

Spam %

Malicious %

Spam + malicious %

1

.uno

62%

37%

99%

2

.sbs

64%

35%

98%

3

.best

68%

29%

97%

4

.beauty

77%

20%

97%

5

.top

74%

23%

97%

6

.hair

78%

18%

97%

7

.monster

80%

17%

96%

8

.cyou

34%

62%

96%

9

.wiki

69%

26%

95%

10

.makeup

32%

63%

95%

11

.autos

93%

2%

95%

12

.today

92%

3%

94%

13

.shop

78%

16%

94%

14

.bid

74%

18%

92%

15

.cam

67%

25%

92%

16

.directory

91%

0%

91%

17

.icu

75%

15%

91%

18

.ml

33%

56%

89%

19

.lol

79%

10%

89%

20

.skin

49%

39%

88%

21

.boats

87%

1%

88%

22

.tattoo

34%

54%

87%

23

.click

61%

27%

87%

24

.ltd

70%

17%

86%

25

.rest

74%

11%

86%

26

.center

85%

0%

85%

27

.fun

64%

21%

85%

28

.cfd

39%

46%

84%

29

.bar

14%

70%

84%

30

.bio

72%

11%

84%

31

.tk

66%

17%

83%

32

.yachts

58%

23%

81%

33

.one

63%

17%

80%

34

.ink

68%

10%

78%

35

.wf

76%

1%

77%

36

.no

76%

0%

76%

37

.pw

39%

37%

75%

38

.site

42%

31%

73%

39

.life

56%

16%

72%

40

.homes

62%