Silly Security: TreasuryDirect.gov is the worst website ever

I saw some content today about savings bonds having a great interest rate. So I tried to sign up. I didn’t know I was going to waste an hour to simply create an account. This has to be the worst website I’ve ever seen.

Somewhere in the middle of the process, after entering a fantastic password generated by my password manager, to log back into the site, I was presented with this virtual keyboard. You are forced to enter your password using the virtual keyboard by clicking on the keys. Entering 40 random characters by clicking on the image is SUPER TEDIOUS.

Not to mention, it took me about 10 attempts to enter the password correctly. I didn’t notice it until getting extremely frustrated, but clicking a button on the virtual keyboard will sometimes double-click the character.

After getting into the site, any attempt to navigate using the browsers forward/back buttons will immediately log you out. As will an accidental double-click on any of the navigation.

It’s a good thing they have a monopoly on savings bonds, because nobody would try to use this and stay sane!

Silly Security: Don’t Show Me The Secret, Then Confirm I Have It!

I just received a replacement credit card from Health Equity because my previous card is expiring. Their validation screens made me laugh.

The first screen shows the card you are replacing, and includes the last four digits of the card.

Then the following screen asks for the last four digits of the card number “In order to verify possession”.

You probably shouldn’t tell me the last four digits before asking me to confirm that I have the card.

Make Sure You Are Calculating Net Promoter Score Correctly

The Net Promoter Score can be a pretty valuable metric for determining customer happiness, and, more importantly, how likely your customers are to tell other people about your product.

The basic idea is that you ask customers how likely they are to recommend your product to someone. Those who respond as a 9 or 10 are considered “Promoters”. When asked about your product, they’ll respond positively and encourage others to use your product as well. Customers who answer with a 7 or 8 are satisfied, but not likely to talk positively about your product. Customers who answer with a six or below are considered “detractors”. When asked about your product, they’ll respond negatively, detracting from your reputation. If you have a higher number of “promoters” than “detractors”, then your NPS Score will be positive. More detractors than promoters will result in a negative NPS score.

There is an excellent tool for calculating your Net Promoter Score at Delighted.com that helps to visualize this.

I was recently meeting with a leadership team and they mentioned that their Net Promoter Score was 6.6. That’s not a great score, but its not terrible. I don’t usually hear it expressed as a decimal, but I didn’t think much of it. After meeting with the team after several months, they kept mentioning NPS Score with a decimal and it had increased to 6.7. It was then that I began to ask questions into how they were calculating that. It turns out it was a simple average on a rating from 1 to 10. That is NOT an NPS Score! If anybody ever tells you their Net Promoter Score is between 1 and 10, make sure to dig in and make sure they are calculating it correctly! Scores should range from -100 (All detractors) to +100 (All promoters).

When calculated correctly, this product’s NPS score was actually negative. That helps to explain why revenue growth has been a challenge and marketing dollars are not moving the needle as they’d like.

Contrast that with another organization I meet with regularly. They calculate their NPS Score correctly and it’s a 60! No wonder this company has incredible growth and is doing well.

While your NPS score is negative, your first priority should be fixing the product and customer experience. Otherwise, every customer that signs up is likely going to detract from others using your product.

How to Think About Annual Contracts, Up-front Payments

I’ve helped several teams lately go through an analysis of when to consider annual prepayments for services. These are some of the decision criteria and metrics that I use to consider if an annual contract or pre-payment should be considered.

As a baseline, calculate the full amount that you would pay monthly. For most software products, this is the regularly advertised price. Make sure you are looking at the actual monthly plan proce though. A lot of services have started advertising as “$x per month billed annually“. Make sure to select the monthly payment price whe you see that. Some services, like commercial insurance charge a small per-payment fee for “installment plans” that should be included.

Next, calculate the full price if paid up-front. Of course, you need to include discounts that are offered. Sometimes, an offer may make it a period other than one year, such as “buy now and get 13 months for the price of 12”, which makes it a little more complex. In that case, you could consider the annual price as 12/13 of the amount you pay. Or, if the extra month is not really material, you may chose to ignore the extea month.

After you’ve got those two numbers (the annual and monthly prices), you should consider the other terms and internal needs.

Consider if your usage of the service is expected to change much over the next 12 months.

Also, consider how much flexibilty you lose with an annual pre-payment. Some services, like Slack give you a credit if usage decreases. Others have no flexibility and you pay that amount, even if usage decreases or you cancel.

In general, I expect around a 15% discount for a full up-front payment and very flexible terms for changes in usage or cancellation. If terms are more strict, I’d aim for more like a 30% (or more) discount for the commitment and up-front payment.

Finally, consider your own cash flow and capital positions. If you have an plenty of cash in the bank, you can lean toward the saving of an annual prepayment. If you don’t have a lot of cash, You’ll favor the monthly terms.

What are your thoughts and experience? What else should be considered when evaluation annual payments?

Using LastPass to Save Passwords and Log In to Multiple AWS Accounts With Two-Factor Authentication

I have multiple businesses, so I log into AWS multiple times per day.

That is a little tricky to do using LastPass since AWS has some hidden form fields that must be filled in
when using two-factor authentication through Google Authenticator.

In order to make it work correctly, I’ve had to modify the extra details in LastPass to add some extra hidden fields. If you set these up in your LastPass credentials for AWS, you should be able to log in with just a couple clicks, like usual, instead of having to type in some of those fields every time or having them overwritten.

Also, make sure to check the “Disable Autofill” checkbox an all of your AWS LastPass entries. Otherwise, one of them will overwrite the hidden form fields on the Two-Factor authentication page

Ubuntu 20.04 Cloud-Init Example to Create a User That Can Use sudo

Use the steps below and example config to create a cloud-init file that creates a user, sets their password, and enables SSH access. The Cloud Config documentation has some examples, but they don’t actually work for being able to ssh into a server and run commands via sudo

First, create a password hash with mkpasswd command:

$ mkpasswd -m sha-512
Password:  
$6$nq4v1BtHB8bg$Oc2TouXN1KZu7F406ELRUATiwXwyhC4YhkeSRD2z/I.a8tTnOokDeXt3K4mY8tHgW6n0l/S8EU0O7wIzo.7iw1

Make note of the output string. You need to enter it exactly in the passwd line of your cloud-init config.

This is the minimal configuration to create a user using cloud-init:

users:
  - name: brandon
    groups: [ sudo ]
    shell: /bin/bash
    lock_passwd: false
    passwd: "$6$nq4v1BtHB8bg$Oc2TouXN1KZu7F406ELRUATiwXwyhC4YhkeSRD2z/I.a8tTnOokDeXt3K4mY8tHgW6n0l/S8EU0O7wIzo.7iw1"
    ssh-authorized-keys:
    - ssh-ed25519 AAAAC3NzaC1lZDI1zzzBBBGGGg3BZFFzTexMPpOdq34a6OlzycjkPhsh4Qg2tSWZyXZ my-key-name

A few things that are noteworthy:

The string in the passwd field is enclosed in quotes

lock_passwd: false is required to use sudo. Otherwise, the system user account created will have a disabled password and will be unable to use sudo. You’ll just continually be asked for a password, even if you enter it correctly.

I prefer the method of adding the user to the sudo group to grant access to sudo. There are other ways to make that work as well, but I feel like this is the cleanest.

Adding any users, will prevent the default ubuntu user from being created.

Google Docs and Sheets should Almost Always be Restricted to Defined Users

Somebody sends you a link to a Google Sheet and it just works. It’s magical.
But that magic comes at a cost. I see far, far too many organizations that regularly share Google Documents and Sheets by using the share with “Anyone with the link” option that Google easily provides.

That is almost ALWAYS a bad idea. The convenience of having it shared with anybody is, at the same time, a potential security problem today and in the future.

But that long link with the 44 random-looking characters would be impossible for somebody to guess, right?

Yes. It would be statistically improbable for somebody to just guess a random string of 44 characters that would result in an actual document. It is possible that an attacker could write programs that could guess millions and millions of links to try them until they found some documents that actually exist. But that’s not the most likely weakness.

Consider what happens when you email a for your spreadsheet to somebody else. You have zero control over who accesses it after that. What if the recipient forwards your email with the link to somebody else? Often emails to businesses are forwarded into Customer Relationship Management (CRM) or similar systems where that link is now accessible to many other people in the organization. What if an attacker has access to a recipients email? Or a CRM system? How about if an employee leaves the company and they still have it in a browser history.

In all of those scenarios, and hundreds more that you can’t imagine, if your document is shared with “Anyone with the link”, literally anybody that sees that link can open it and you have absolutely no knowledge that they did.

Always share only with specific email addresses.

Sharing with Google Groups

Sharing with specific people can become a headache to maintain as people change roles. Consider using the Google Groups feature in your organization. You can set up a Google Group for something like ‘client-yourclientname@myorganziation.com’ or ‘team-myteamname@myorganization.com’ and ask to have documents shared with that group instead of individual people. You can then add and remove people from the groups to provide access to only those that are allowed.

See More information about sharing with Groups at https://support.google.com/a/users/answer/9308872?hl=en

Solving ECS Stuck in Pending and Frozen / Stalled ECS Hosts Problems

We’ve had a strange, hard to track-down problem for months now. It has felt like a bug with Amazon ECS, but everything seems to have been working correctly.

The main way that we’ve observed this problem is that ECS would say that it was launching tasks, but they would stay in a “PENDING” state forever. Conversely, when tasks needed to be killed, the desired state would change to Stopped, but the ECS Console would indicate that they were still running. We discovered quickly, that some of our ECS Host Servers would become completely unresponsive. Sometimes with 100% CPU usage, sometimes with near zero CPU Usage. Terminating the instance, and having the Auto-Scaling group recreate it would generally solve the problem, but its never good to have things frozen without understanding why.

Often, the host servers would be completely unresponsive. We were usually unable to SSH into the server to investigate. When able to access them, looked through logs and found it full of failures about being unable to talk to external resources. After diving pretty deep, we figured out that the route table was missing a default gateway. It’s hard to talk to anything when you can only use a local network.

This is an example of a missing default gateway.

[ec2-user@ip-172-31-45-74 ~]$ route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
172.31.32.0     0.0.0.0         255.255.240.0   U     0      0        0 eth0

On a functioning instance, it should look like this. Notice the destination of 0.0.0.0 with the IP Address to the Default Gateway:

[ec2-user@ip-172-31-39-228 ~]$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.31.32.1     0.0.0.0         UG    0      0        0 eth0
169.254.169.254 0.0.0.0         255.255.255.255 UH    0      0        0 eth0
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
172.31.32.0     0.0.0.0         255.255.240.0   U     0      0        0 eth0

It was puzzling how the machine would work for a while, and then its default gateway would disappear.

I’m still not certain how exactly that is happening. However, the system log indicates that there is a period of extremely high load
and it gets frozen for minutes (maybe hours) at a time.

Some of these log entries are indicitive of major delays:

Jan 20 13:26:44 ip-172-31-123-45.ec2.internal crond[21992]: (root) INFO (Job execution of per-minute job scheduled for 13:25 delayed into subsequent minute 13:26. Skipping job run.)

Jan 17 21:20:31 ip-172-31-45-166.ec2.internal chronyd[2696]: Forward time jump detected!

Notice how these logs are out of order too:

Jan 20 13:39:22 ip-172-31-123-45.ec2.internal kernel: R13: 00007faf9dc777a8 R14: 00000000000031f9 R15: 00007faf9dc7d510
Jan 20 13:28:30 ip-172-31-123-45.ec2.internal dockerd[4660]: http: superfluous response.WriteHeader call from github.com/docker/docker/api/server/httputils.MakeErrorHandler.func1 (httputils.go:107)
Jan 20 13:36:03 ip-172-31-123-45.ec2.internal dhclient[3275]: XMT: Solicit on eth0, interval 129760ms.
Jan 20 13:28:30 ip-172-31-123-45.ec2.internal dockerd[4660]: http: superfluous response.WriteHeader call from github.com/docker/docker/api/server/httputils.MakeErrorHandler.func1 (httputils.go:107)

Finally, this may be the thing that ultimately disables the networking. It looks like `oom-killer` killed the `dhclient-script`, which maybe left the network in an very bad state:

Jan 20 15:28:36 ip-172-31-45-74.ec2.internal kernel: dhclient-script invoked oom-killer: gfp_mask=0x14201ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD), nodemask=(null),  order=0, oom_score_adj=0
Jan 20 15:28:36 ip-172-31-45-74.ec2.internal kernel: dhclient-script cpuset=/ mems_allowed=0

You can simply run

sudo dhclient eth0

to have it grab the default gateway from DHCP again. But its best to put other memory limits in place to prevent it from running out of resources to begin with.

Find MySQL indexes that can be removed to free up disk space and improve performance

I wrote this handy query to find indexes that can be deleted because they have not been in use. It
queries the performance_schema database for usage on the indexes, and joins on INFORMATION_SCHEMA.TABLES
to see the index size.

Indexes that have zero reads and writes are obvious candidates for removal. They take extra write overhead to keep them
updated, and you can improve performance on a busy server by removing them. You can also free up some disk space
without them. The size column below helps to understand where you have the most opportunity for saving on disk
usage.

mysql>
SELECT. OBJECT_NAME,
        index_name,
        SUM(INDEX_LENGTH) AS size,
        SUM(count_star) AS count_star,
        SUM(count_read) AS count_read,
        SUM(count_write) AS count_write
FROM  table_io_waits_summary_by_index_usage
JOIN information_schema.TABLES
    ON table_io_waits_summary_by_index_usage.OBJECT_SCHEMA = TABLES.TABLE_SCHEMA
   AND table_io_waits_summary_by_index_usage.OBJECT_NAME = TABLES.TABLE_NAME
WHERE OBJECT_SCHEMA LIKE 'mydatabase%'
GROUP BY object_name, index_name
ORDER BY count_star ASC, size DESC
LIMIT 20;

+------------------------------+---------------------------------+-------------+------------+------------+-------------+
| OBJECT_NAME                  | index_name                      | size        | count_star | count_read | count_write |
+------------------------------+---------------------------------+-------------+------------+------------+-------------+
| transactions                 | order_id                        | 42406641664 |          0 |          0 |           0 |
| transactions                 | msku-timestamp                  | 42406641664 |          0 |          0 |           0 |
| transactions                 | fkTransactionsBaseEvent         | 42406641664 |          0 |          0 |           0 |
| baseEvent                    | PRIMARY                         | 33601945600 |          0 |          0 |           0 |
| baseEvent                    | eventTypeId                     | 33601945600 |          0 |          0 |           0 |
| orders                       | modified                        | 20579876864 |          0 |          0 |           0 |
| orders                       | buyerId-timestamp               | 20579876864 |          0 |          0 |           0 |
| productReports               | productAd-date-venue            |  8135458816 |          0 |          0 |           0 |
| shipmentEvent                | id                              |  7831928832 |          0 |          0 |           0 |
| shipmentEvent                | eventTypeId                     |  7831928832 |          0 |          0 |           0 |
| historyEvents                | timestamp_venue_entity          |  4567531520 |          0 |          0 |           0 |
| targetReports                | venueId-date-targetId           |  3069771776 |          0 |          0 |           0 |
| productAds                   | venue-productAd                 |  1530888192 |          0 |          0 |           0 |
| keywords                     | venue-keyword                   |   895598592 |          0 |          0 |           0 |
| targetingExpressions         | venue-target                    |   215269376 |          0 |          0 |           0 |
| targetingExpressions         | rType-rValue                    |   215269376 |          0 |          0 |           0 |
| serviceFeeEvent              | PRIMARY                         |    48234496 |          0 |          0 |           0 |
| serviceFeeEvent              | id                              |    48234496 |          0 |          0 |           0 |
| serviceFeeEvent              | eventTypeId                     |    48234496 |          0 |          0 |           0 |
| adGroups                     | venue-adGroup                   |    42336256 |          0 |          0 |           0 |

MySQL Encryption In-Transit Does NOT Require Client-Side Certificates

There are many articles around the Internet that discuss enabling Encryption in-transit to MySQL servers. They all include instructions about creating Client Certificates, but they don’t clearly explain that Client-Side Certificates are not a requirement to achieve end-to-end encryption between client and server.

Creating Client certificates that can be authenticated by the server can be complicated. It is not even possible in some scenarios, such as using servers hosted by AWS RDS, since AWS runs its own Certificate Authority. But don’t let that stop you. Below, I will demonstrate that enabling SSL/TLS on the server, and using a client that supports encryption is sufficient to securely encrypt traffic between the two.

First, I set up a MySQL server on RDS using MySQL version 8.0.25. Nothing special here, except that I’m going to make it “Publicly Accessible” which gives is a Public IP Address so that I can access it over the Internet. My Security Group here already allows inbound port 3307 from my desired IP Addresses for testing:

aws rds create-db-instance \
    --db-instance-identifier=encryption-tester \
    --allocated-storage=20 \
    --db-instance-class=db.t3.micro \
    --engine=mysql \
    --master-username=admin \
    --master-user-password="thepasswordIchose" \
    --vpc-security-group-ids="sg-0bf6fa7080100e55b" \
    --backup-retention-period=0 \
    --port=3307 \
    --no-multi-az \
    --engine-version=8.0.25 \
    --publicly-accessible

It takes several minutes for my Database Instance to be created, then I can log into it with the command:

mysql -h encryption-tester.accountidstuff.us-east-1.rds.amazonaws.com -u admin --port=3307 -p

I run the command show status like 'ssl_cipher'; and look at that! My connection is encrypted already, as indicated by Cipher method present:

$ mysql -h encryption-tester.accountidstuff.us-east-1.rds.amazonaws.com -u admin --port=3307 -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 17
Server version: 8.0.25 Source distribution

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> show status like 'ssl_cipher';
+---------------+-----------------------------+
| Variable_name | Value                       |
+---------------+-----------------------------+
| Ssl_cipher    | ECDHE-RSA-AES128-GCM-SHA256 |
+---------------+-----------------------------+
1 row in set (0.01 sec)

I haven’t set up any client certificates or anything special, yet my connection is encrypted. But let’s not take the session variable’s word for it. Lets double-check by capturing and inspecting some packets.

I’ll run tcpdump with this command:

sudo tcpdump -i any host encryption-tester.accountidstuff.us-east-1.rds.amazonaws.com  -s 65535 -w /tmp/initial-connection.pcap

To make it quick, Instead of using a full packet-analysis program, I just run the strings command to look for text strings in the packet capture:

17:05 $ strings -8  /tmp/initial-connection.pcap
=JpgP~eS
mysql_native_password
Washington1
Seattle1"0
Amazon Web Services, Inc.1
Amazon RDS1%0#
Amazon RDS us-east-1 2019 CA0
210824170035Z
240822170850Z0
:encryption-tester.accountidstuff.us-east-1.rds.amazonaws.com1
Amazon.com1
Seattle1
Washington1
Seattle1
Washington1"0
Amazon Web Services, Inc.1
Amazon RDS1 0
Amazon RDS Root 2019 CA
:encryption-tester.accountidstuff.us-east-1.rds.amazonaws.com0
Seattle1
Washington1"0
Amazon Web Services, Inc.1
Amazon RDS1 0
Amazon RDS Root 2019 CA0
190919181653Z
240822170850Z0
Washington1
Seattle1"0
Amazon Web Services, Inc.1
Amazon RDS1%0#
Amazon RDS us-east-1 2019 CA0
HId0%aC>

Looks like a lot of stuff in that output about the certificate and SSL negotiation, but nothing containing the queries I executed.

I’m going to try it again and specifically disable encryption to see what the packets look like and ensure they contain the plain-text statements and responses I expect:

This is my SQL session:

17:05 $ mysql --ssl-mode=DISABLED -h encryption-tester.accountidstuff.us-east-1.rds.amazonaws.com -u admin --port=3307 -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 32
Server version: 8.0.25 Source distribution

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> select version();
+-----------+
| version() |
+-----------+
| 8.0.25    |
+-----------+
1 row in set (0.00 sec)

mysql> show status like 'ssl_cipher';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Ssl_cipher    |       |
+---------------+-------+
1 row in set (0.01 sec)

mysql> \q

The strings in the packets captured during that session clearly contain things relevant to the commands that I executed:

17:05 $ strings -5 /tmp/skip-ssl.pcap
1%aCu
1%a\u
8.0.25
*Bi|tm
UkU-dsK
mysql_native_password
admin
mysql_native_password
Linux
_client_name
libmysql
24817
_client_version
5.7.35  _platform
x86_64
program_name
mysql
select @@version_comment limit 1
@@version_comment
Source distribution
select version()
        version()
8.0.25
show status like 'ssl_cipher'
performance_schema
session_status
session_status
Variable_name
Variable_name
performance_schema
session_status
session_status
Value
Value
Ssl_cipher

Conclusion:

SSL Client-Certificates are NOT required for traffic to be encrypted to a MySQL server. In fact, with a modern client and server, SSL is preferred and is automatically enabled. Just like I’d expect for traffic to be encrypted by default in 2021.

So what is the purpose of Client Certificates during a MySQL Connection

Client Certificates are intended to verify the identity of the Client. They are an extra step of authentication beyond a typical username and password. By presenting a client certificate that has been properly signed by a recognized Certificate Authority, the client is proving that their identity or system has been verified by the Certificate Authority.

Because SSL is complicated and is not well understood, many well-meaning people have instructions for creating a client key and client certificate, and transmitting those to authorized users. While that does provide a second piece of information needed to authenticate to the server, it is not how a secure client should authenticate.

The proper, fully secure method for a client to get a certificate is for the client to create its own private key. It should never share that key, even with the Certificate Authority. With the private key created, it would then create a certificate signing request (CSR), and present only the certificate signing request to the Certificate Authority. The certificate authority takes whatever steps it requires to verify the authenticity of the client, then provide the client back with a Client Certificate signed by the Certificate Authority. That Client Certificate is the client’s evidence that it’s identity has been verified by the Certificate Authority. The Certificate Authority is able to provide the client certificate without ever having the client’s private key.

Best Practices

If you run a MySQL Server and want to require that all clients to connect via SSL/TLS, you can set the global setting require_secure_transport to true. To require SSL only for specific users, use the CREATE USER ... REQUIRE SSL statement when creating the MySQL user