Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (2024)


In November 2020, the Japanese government's Minister of Digital Transformation, Takuya Hirai, announced that the Cabinet Office would discontinue the use of password-protected zip file email attachments (PPAP) for security reasons.

In today’s article, we will provide an overview of PPAP, its problems, and safe alternatives.

What is PPAP?

Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (1)

PPAP refers to the process of sending an encrypted file (with password) attachment in an email and then sending the password to unzip the file in a second email. As a part of security measures, this method is used by many companies and organizations, as well as government agencies in Japan.

The abbreviation "PPAP" was coined by IT consultant, Akira Ootaishi, and comes from the following terms (*1):

  • P: Password-protected file is sent.

  • P: Password is sent separately.

  • A: Encryption (“angouka” in Japanese)

  • P: Protocol

Do other countries use PPAP, or is it only used in Japan?

Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (2)

While PPAP is a common security measure in Japanese companies, in fact, it is rarely seen overseas where password-protected zip files tend to be viewed suspiciously and treated as potential virus vectors.

It is not clear why PPAP has become so popular in Japan, but it seems to be one of the unique business practices that have developed in Japan.

The history of PPAP

PPAP is widely used in Japanese companies, and in many cases, its use is even an official company security policy.

The origins of this practice can be traced back to the early days when email was first used for business purposes, and this method of sending password-encrypted zipped files by email and then providing the password through another channel (fax, paper document, etc.) was developed as a security measure.

The above method was thought to be useful in becoming a Privacy Mark certified entity and spread rapidly in Japan. However, faxing or sending paper documents became too cumbersome, so it was gradually decided that passwords could also be sent by email, simplifying the method. As a result, the use of PPAP in Japan has remained unchanged to this day.

Why is PPAP dangerous? Why is it being abolished by the Japanese government?

As mentioned at the beginning of this article, the Cabinet Office has decided to abolish the use of PPAP. (*2) In response, the Japan Institute for Promotion of Digital Economy and Community (JIPDEC), which operates the Privacy Mark system, has also officially announced the organization has never endorsed PPAP. (*3)

However, why is PPAP considered dangerous, and why is there a growing trend to abolish it? Below are five reasons:

▼ Sending encrypted zip and password separately by email provides limited protection.

There is little point in sending a password-protected zip file and the password in separate emails if hackers can access the email system. If the first email with the attachment is accessible, the second email with the password will be equally compromised.

▼ Security software cannot detect viruses in attachments.

Currently, many security software programs automatically scan email attachments for viruses. However, if the attached file is zipped and encrypted, security software will not be able to check the contents. In other words, if the file contains a virus, it is likely to be delivered to your inbox undetected.


Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (3)

▼ Zip files encrypted with passwords are at high risk of compromise.

Passwords-encrypted zip files are considered in the industry to be relatively simple to crack. Unlike website logins, encrypted zip files are easy for cybercriminals to access because unlimited password attempts are allowed.

▼ Emails may be vulnerable to interception or access in transit.

Emails pass through multiple servers between the time it is sent and received by the final party. If any part of an email is not properly encrypted, an attacker can easily eavesdrop on the contents. Therefore, passwords written in plain text are extremely dangerous.

▼ Wasteful measures reduce work efficiency

The PPAP process requires a great deal of time and effort on both the part of the sender and the receiver. Multiple steps are necessary to create and send the encrypted file by the sender. The receiver has to access the PPAP system via the first email, then open the second email to copy and paste the password. This inefficiency can result in a decrease in productivity.


Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (4)

Let us look at an alternative to PPAP for businesses to send and receive files securely.

▼ Cloud storage is the safest measure.

The most secure alternative to PPAP, and one that is actually used most often, is the use of cloud storage to send and receive files. With cloud storage, specifically, files are often shared in the way described below.

For this article, we will use our Tsukaeru Filebako cloud file sharing service (client version) as an example.


Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (5)

After installing the Tsukaeru Filebako desktop client, files can be easily shared in the familiar Explorer format.

The beta version, scheduled for an early 2021 release, will allow passwords to be added to public links directly from Explorer, without having to access the browser version (web version).

1.Right-click on the file name to share and then select “Create Public Link.”

2.The password can be directly entered in the pop-up window that appears.


The password-protected file can be easily shared by providing the recipient with the created link.

The ability to share files via URLs with cloud storage solves all of the potential PPAP problems. There is no need to encrypt the file each time they are sent or send multiple emails.

▼ 2FA (two-factor authentication) settings provide even greater security.


Recently, two-factor authentication has been increasingly implemented as a security measure to prevent identity theft and unauthorized logins. In the past, users were only authenticated with an ID and password when logging in. However, now, another level of authentication is being added to strengthen the identification process.

Of course, this two-factor authentication feature is also available with Tsukaeru Filebako.

To implement, select “Security” then “Two-Factor Authentication” from the settings screen, and choose between "Email Address" or "Application."


Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (6)

If email address authentication is chosen, recipients will receive by email the authentication code needed to log in.


Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (7)

▼ Tsukaeru Filebako provides reliable security.

When choosing a cloud storage service, robust security measures are extremely important. For this reason, we recommend Tsukaeru Filebako, the cloud storage service from Tsukaeru mentioned earlier.


Tsukaeru Filebako is a full security, cloud storage service that is hosted on its own servers in Japan and allows the setting of expiration dates for shared links and the remote deletion of device data. It can be installed on the same day, is easy to use even for beginners, and has an affordable and simple fee structure.

A two-week free trial is also available (completely free of charge with no need to sign a contract!). Please take advantage of this opportunity to try it out for yourself.

Click here for Tsukaeru Filebako details.
Sign up for a free Tsukaeru Filebako trial.
Contact us at Tsukaeru.

<Sources>
*1

Workplace Reform Starting with Changing the Habit of Attaching Files to Emails (PDF, Japan Institute for Promotion of Digital Economy and Community)

2*

Automatic Encryption ZIP Files Discontinued by Cabinet Office; Cabinet Secretariat - Digital Minister: "Inappropriate" (Nihon Keizai Newspaper)


*3

Sending files as email attachments (Japan Information Processing Development Corporation)

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Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? (2024)

FAQs

Five reasons to stop using password-protected zip file email attachments: Why is it so dangerous? ›

Zip files encrypted with passwords are at high risk of compromise. Passwords-encrypted zip files are considered in the industry to be relatively simple to crack. Unlike website logins, encrypted zip files are easy for cybercriminals to access because unlimited password attempts are allowed.

Why is a .zip file dangerous? ›

What makes . ZIP archives dangerous? Files containing viruses, malware and other malicious content can be compressed together into . ZIP archives and jointly bypass weakly configured upload security policies.

Why do I need to password protect my email attachments? ›

If you need to send sensitive or confidential information via email, you might want to password protect your attachment. This way, only the intended recipient can open and view the file, and you can prevent unauthorized access or data breaches.

Can password-protected files be malware? ›

Malicious password-protected archive files are designed to deceive users and bypass commonly deployed inspection engines to deliver malware and ransomware down to a user's endpoint.

Is a zip file secure in email? ›

One thing to keep in mind though is that if you're sharing confidential information, you'll need to encrypt the zip file before sending it via email. Email on its own does not protect your information whatsoever.

What are the disadvantages of zip files? ›

The Disadvantages

They include file size limits, file type limits, corruption, and mobility issues. One of many disadvantages associated with ZIP archive files is compression limits. Some files cannot be compressed much more than they already are. This is especially true for MP3 files and JPG files.

What are the disadvantages of using zip files? ›

Drawbacks of Using a Zip File
  • One of the major drawbacks of a Zip file is that it has a compression limit. ...
  • Zip files get corrupted and accurate extraction of files becomes very challenging.
  • The entire Zip file will be affected directly by any kind of damaged data and information.
  • It might become unencrypted also.

How secure is a zip file with password protection? ›

▼ Zip files encrypted with passwords are at high risk of compromise. Passwords-encrypted zip files are considered in the industry to be relatively simple to crack. Unlike website logins, encrypted zip files are easy for cybercriminals to access because unlimited password attempts are allowed.

Are zip files a security risk? ›

While zip files are not inherently dangerous, they have become a favorite format for cybercriminals running phishing campaigns, injecting ransomware, and deploying other malicious actions to unleash malware on unsuspecting individuals.

Can hackers access password protected files? ›

Yes, hackers can potentially crack password-protected Word documents using various techniques such as brute force attacks, dictionary attacks, and social engineering.

Why do companies block zip files? ›

Preventing Exploitation of the ZIP File Format. ZIP files are a known vector for phishing campaigns, ransomware and other malicious action.

Can you password protect a zip folder before emailing? ›

Zipped folder

In Windows Explorer, highlight and right-click on the files you would like to put into a zipped file. Select Send to, then Zip folder (compressed). Follow the prompts to name and save the folder. Double-click the zipped file, then select File and Add Password.

Are zip files blocked by Gmail? ›

Even if you have taken steps to compress files into a Zip file, Gmail will block the attachment if it detects a prohibited file format within the archive file. WinZip Enterprise gives you options for navigating file blocking, such as configuring file extension options using WinZip Courier.

Can zip files hold viruses? ›

A zip file definitely can contain a virus infected file, but you would have to execute the file and whatever security software you have on your system would have to allow that. You don't even say what device or OS you use, hard to say more.

Do hackers use zip files? ›

"ZIP files are often used as part of the initial stage of an attack chain, typically being downloaded after a user accesses a malicious URL or opens an email attachment," Trend Micro said.

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