Attacking Password Managers: LastPass

This is the second post in a series I have done looking at password managers. My first post was on KeePass and covered some techniques which can be used against local password managers.

For this post, LastPass will be used as an example of a cloud-based password manager. In my opinion, these managers often have better UI/UX, so are easier for non-techy people to use.

LastPass has unfortunately had a *pretty rough* history, with several high-profile breaches in 2015, August 2022 and November 2022. Despite this, I would consider it as one of the most popular password managers – so it is worth using for this post!

There are several methods which I will cover here, most of which will apply to any cloud/browser-based password manager:

I was only able to successfully access the vault through the ‘Remote Debugging – Accessing The LastPass Vault’ section. With the other techniques I was able to get to a position where I believe I had the correct cookies or position, but I was unable to successfully load the vault. I suspect this is due to LastPass performing host or session checking – but it could well also be due to me needing to get better at Pass-The-Cookie attacks!

Dumping Saved Credentials

To dump any saved Chrome passwords, we can use SharpChrome with the logins /password:PASSWORD parameters. This does require us to get the plaintext password of the user, but there are many ways of obtaining this 😉

To dump other Chromium based browsers such as Brave or Edge, we can use the /browser flag. For example, we would use the following command to interact with an Edge browser: SharpChrome.exe logins /password:PASSWORD /browser:edge

One thing to bear in mind with this approach is that LastPass will detect new sign in locations, such as different browsers, IP addresses and so on – so we cannot dump creds for LastPass and login directly to it!

Dump The LastPass Vault From Memory

For LastPass to work as an extension, it loads the vault into memory – but there are some weaknesses in the way in which it does this. Notably a BlackHat talk from 2015 covers this in technical detail if you are interested.

Luckily TrustedSec have automated a lot of this with their lastpass BOF, which is covered in an excellent 15-minute demo on YouTube. The BOF is part of their ‘CS-Remote-OPs-BOF‘ repository

To start with, I will ensure that the LastPass extension is logged in but I will not have LastPass.com open in Chrome

I will then use Cobalt Strike to list the processes and pass the PIDs for Chrome processes into the lastpass BOF.

It will begin to parse memory and dump out any relevant strings, for example the master password:

As well as credentials from within the vault:

I did find that the BOF would only pull credentials from the vault after I had specifically searched for them in the extension, though it did appear as if LastPass have altered the way in which the extension works since the BOF was written, as the parsing was a little off when I used it. Nonetheless, this is a great BOF and serves as a very useful starting point for parsing Chrome’s memory.

Session Theft – Browser Pivoting

If our target has authenticated into LastPass, we can use Cobalt Strike’s Browser Pivot feature to leverage this already-established connection, but the target would have to be using Internet Explorer 😔.

We can use FoxyProxy to route our traffic through the HTTP proxy which CS has established

After adding an exception and relaxing rules on HSTS and the network.stricttransportsecurity.preloadlist option, this did partially load LastPass, but I had issues with it successfully loading the vault.

Session Theft – Cookies via DPAPI

I then turned to dumping values via DPAPI, which was a bit of a struggle. I believe that Chrome has altered the way in which it stores cookies, which prevents some of the ‘older’ tooling from working automagically. To counter this, I went to the Chrome/User Data folder on my test lab and searched for ‘cookie’, revealing the new location!

It turns out that the Cookie DB is within %LOCALAPPDATA%\Google\Chrome\User Data\Default\Network, which isnt where SharpChrome looks – most other blog posts mention to look in the \Default\Cookies folder. We can use this file path in SharpChrome to dump the cookies using the following command:

SharpChrome.exe cookies /target:"C:\Users\vagrant\AppData\Local\Google\Chrome\User Data\Default\Network\Cookies" /password:PASSWORD

Looking at the documentation, we need to provide this with the /statekey:X parameter. We can obtain these values by running SharpChrome.exe statekeys

We will use the value ***EC73E9 for the /statekey parameter, and will also use the /url parameter to only include cookies for lastpass. This leaves us with the final command:

execute-assembly /home/user/SharpChrome.exe cookies /target:"C:\Users\user\AppData\Local\Google\Chrome\User Data\Default\Network\Cookies" /password: /statekey:YADDAYADDA_EC73E9 /url:lastpass /format:json

This /format:json allows us to export directly into the Cookie-Editor extension.

Remote Debugging – Accessing The LastPass Vault

At this point I started looking into the remote-debugging-port technique which has been covered a lot recently. I then stumbled upon MDSec’s post which covered the technique below in far greater (and better) detail – go check out their post!

I found that using a redirector and the CS SOCKS proxy was very slow in my lab, even when using an interactive beacon so is probably too intensive for real world usage unless you absolutely need to! Ultimately I used Chisel to directly connect from the target to my team server, in the real-world you would want to ensure this is way more locked down!

To start, I spawned Chrome with chrome.exe --remote-debugging-port=10999. As covered elsewhere, there is a --headless argument which wont create a GUI window, but I had serious issues getting it to work!

Following a lot of errors, I realised we need to Chrome with the victims own user profile. I didn’t have success specifying a user profile directory, but did have success just using --profile-directory="Default". I believe that this profile directory value can change depending on how the target’s environment is configured – so this might change!

Using Chromium I used the flags described within the MDSec blog post to use the Chisel SOCKS proxy inside Chrome:

--proxy-server="socks5://127.0.0.1:1080" --proxy-bypass-list="<-loopback>"

This did appear to work on Chromium in Ubuntu 22.04 – but it would not successfully load the LastPass Vault for me. Instead I used a Windows VM with Chrome to more closely mimic the target user’s environment.

To get the remote debugging URL, we need to visit http://localhost:10999/json/list and get the devtoolsFrontendUrl value.

Then we can use the following magic URL from MDSec to spawn a new instance of the LastPass vault extension:

localhost:10999/json/new?chrome-extension://hdokiejnpimakedhajhdlcegeplioahd/vault.html

We then visit /json/list to see that it has spawned a new instance

Which we can then visit in our attackers browser which we started earlier.

The demo above will replicate any actions you take onto the targeted users desktop. This is has obvious, significant drawbacks so would require some *heavy* social engineering to work if you pursue this method without using the headless mode or another technique!

Ultimately, I couldn’t get this to work in headless mode through Firefox and Chromium on an Ubuntu machine. I suspect that this is a combination of:

LastPass is likely doing some sort of host checking, which fails when using a different host to the target (Windows/Chrome vs Ubuntu/Chromium&Firefox)
Using headless mode introduced other errors
Lack of ability

Remote Debugging – Accessing Cookies Via The Debug WebSocket

Accessing the vault via a GUI felt like a pretty long winded and noisy way of accessing LastPass. I did some hunting on Google and found a post by SpecterOps on dumping cookies via the debug port which we were using in the previous example.

This post mentions the CookieNapper tool by GreyCatSec, which uses WebSockets exposed by the debug port to simply query for all of the cookies. This has several advantages:

No need to use SharpChromium or load extra binaries
Invisible to the user
Should have less latency as the attack would require less usage of proxies

Using the SOCKS proxy we set up with Chisel, we can use the tool to dump cookies:

From here, we can use the EditThisCookie extension to import the cookies. Again I had issues getting access to the vault, but the cookies did appear to be successfully dumped.

Summary

In summary, I learned a lot digging into these 2 password managers – in no particular order:

KeePass has a number of pretty significant design flaws, even in the latest version
The backdooring of KeePass via the trigger system is pretty neat
Scanning memory is a really handy technique for password managers and programs such as these…
I need to improve at pass-the-cookie attacks
- Or just don’t target LastPass I guess ¯\_(ツ)_/¯
Password managers are still a very good solution, and are hugely more secure than other solutions (Cough passwords.xlsx)

For what its worth, I think LastPass (or more broadly cloud-based password managers) are the best solution for most users. They tend to be much more usable than local applications such as KeePass, which should in theory encourage end users to use it more, thus making their credentials more likely to be more secure. For more technical or computer-savvy users, KeePass is ultimately more secure from an architectural point of view in my opinion.

That being said, cloud-based password managers are a huge target for attackers and you do end up putting a lot of trust into the provider, rather than an endpoint which is under your control. With LastPass now having suffered multiple breaches, this is an area which attackers will continue to target!

Attacking Password Managers: KeePass

In this two-part blog post, Ill be taking a look into attacks password managers to improve my knowledge on techniques which can be used against them. To start with, I will take a look at local password managers by looking at the sort of techniques which can be used against KeePass. The second post covers some attacks against LastPass.

Ill start by covering some generic attacks against password managers (Both local and cloud-based), before moving onto KeePass-specific attacks.

Generic Password Manager Attacks

Monitoring/Grabbing the Clipboard contents

We can do this within Cobalt Strike using the clipboard command. This is only a point-in-time grab of the data, and will not actively monitor it!

We can also use Mimikatz to do this with misc::clip, but this is way overkill for most situations

Keylogging

If we are feeling patient (or want to coerce the target into opening their password manager), we can grab the master password by keylogging their system to capture the main password.

KeePass Attacks

Now lets look into some KeePass-specific attacks. This was all performed against v2.52 which was the latest at the time! This was installed with all the default settings, and the TopSecretStuff.kdbx file is using a password of ‘infected‘.

And lets add a password or 2 to our KeePass database

KeeThief

KeeThief is another great tool from GhostPack. It was originally released 7 years ago and targets .NET 3.5, which meant I had to install the framework on my test system. For real-world usage, make sure you adapt this to your target environment!

I then had to combine the Microsoft.Diagnostics.Runtime.dll DLL into the KeeThief executable and make the entry point public to avoid getting an “Invoke_3 on EntryPoint failed” error in Cobalt Strike. To do this, I used ILMerge which was downloaded as part of building KeeThief. Using the csproj file from KeeThief for guidance, the final command was:

PATH_TO_KEETHIEF\KeeTheft\packages\ILMerge.2.14.1208\tools>ILMerge.exe /target:winexe /targetplatform:"v2,C:\Windows\Microsoft.NET\Framework\v2.0.50727" /target:exe /out:test.exe "PATH_TO_KEETHIEF\bin\Release\KeeTheft.exe" "PATH_TO_KEETHIEF\bin\Release\Microsoft.Diagnostics.Runtime.dll"

I also did the same for the associated PowerShell file which this should produce, using the command:

PATH_TO_KEETHIEF\PowerShell>powershell -exec bypass -File Out-CompressedDll.ps1 KeeThief.exe KeeThief.ps1

The commands are covered in the README of KeeThief

Finding KeePass files

Using the pre-built KeePassConfig.ps1 file, we can hunt in a system for KeePass XML files. These XML files contain the configuration data for KeePass which we will modify later on as part of an attack!

Stealing the master password from memory

We can now simply run the KeeThief tool against our system, and so long as KeePass is running, we can steal the plaintext master password. Notably KeePass just needs to be running on the system and be unlocked with the main password – a pretty typical arrangement for most users who use KeePass!

We can also do this using the KeeThief.ps1 script if we want to throw it back to 2017, with the Find-KeePassDatabaseKey cmdlet.

From this point, we could steal the TopSecretStuff.kdbx file, and interact with it away from the host.

Backdooring the trigger system

As mentioned in an older Mandiant report, KeePass includes a ‘trigger’ system which can be exploited. In short, this trigger system allows specific actions or commands to be run when specific criteria are met in KeePass. Mandiant’s example is to dump out the KeePass DB whenever KeePass is opened. On the 23rd January 2023, CVE-2023-24055 was released for this, but is disputed by KeePass.

As covered in the comments of KeePassConfig.ps1, we need to pipe the output of Find-KeePassConfig into Get-KeePassConfigTrigger for it to work.

This didn’t work with me, after a bit of debugging I believe the structure of the KeePass config has likely changed since the tool was created, or the tool had revealed a false positive file. Below is an example of the error within the Add-KeePassConfigTrigger function

After manually creating a Trigger on the target system, the C:\Program Files\KeePass Password Safe 2\KeePass.config.xml file had not changed and was essentially an empty XML file

<?xml version="1.0" encoding="utf-8"?>
<Configuration xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Meta>
   <PreferUserConfiguration>true</PreferUserConfiguration>
  </Meta>
</Configuration>

This would explain why PowerShell was throwing an error, as there were no XML elements for it to add nodes onto! With a bit of hunting, I found the file at %APPDATA%/Roaming/KeePass/KeePass.config.xml

We can now pipe this file path into Find-KeePassConfig and then into Add-KeePassConfigTrigger like so:

"C:\Users\vagrant\AppData\Roaming\KeePass\KeePass.config.xml" | Find-KeePassConfig | Add-KeePassConfigTrigger -Verbose

We can confirm this by looking at the KeePass.config.xml file after running the command

Before we restart KeePass, note that there are no files in the %APPDATA%/Roaming/KeePass folder

After signing into KeePass, a file named TopSecretStuff.csv is dropped into the folder

Which we can open to reveal our passwords

We can then remove our configuration change by running Remove-KeePassConfigTrigger

Cracking A KeePass file

The above attacks have relied on us compromising a system where the user is either actively using KeePass, or will routinely use it. What if we come across a user which only infrequently uses it, or find a *.kdbx file on a share?

For this, we can use the keepass2john executable from John The Ripper – which is built into Kali. If you are using a different OS, then Harmj0y has made a Python script to do this!

We now have our hash:

Looking at the example hashes from Hashcat (Mode 13400), we can see that we will need to remove the database name ‘TopSecretStuff‘ from the beginning of this string

We can then run Hashcat using mode 13400 to try and crack this

hashcat.exe -a 0 pass.txt rockyou.txt -m 13400

Additional Persistence Methods

Something which I read about, but didn’t attempt was obtaining persistence via the KeePass plugins, which is covered by @two06 on Medium, they also have another post which covers another way of abusing the trigger system to execute arbitrary code, in a similar way to KeeThief’s persistence method.

In my second post in this series, I will take a look at LastPass as an example of a cloud/browser-based password manager!

Shodan 201: Rummaging Around The Internet

Shodan is a well known resource which is one of my go to tools for OSINT and technical enumeration. This post will cover how we can use Shodan filters in a slightly more advanced way to hunt for resources.

I will start by covering some of the basics, before diving into filters and then ending by covering some more complex queries.

Overview

At a very basic level, Shodan routinely scans every port on every host on the internet and then ingests this into their platform. This means we can query _the whole internet_ to find details on hosts. This has a few advantages:

As an attacker, as we can passively enumerate targets without having to actively interact with them
This data is gathered continuously by Shodan, so it is always quite up to date
All of this can be queried through the website, or API
- With the API, we can automate this.. 😉

Without an account we can still do some limited searching but the real value comes from having a paid account so we can use filters. In the past, they have had a sale on Black Friday.

This post will assume we have a paid account, but as a free user, we can still search for phrases, such as those which contain the word hacked in their response.

And we can also look up specific IP addresses, such as Google’s DNS server at 8.8.8.8:

Filters

Shodan has a page which lists all of the filters available. I wont delve into all of them in this post as some are fairly straightforward, and Shodan itself has a great reference page for this purpose. Instead I will look at some of the more interesting ones.

Screenshots

There are several ways of querying for screenshots in Shodan. We can check if a host has an associated screenshot with the has_screenshot parameter:

has_screenshot:true

We can also search for text within screenshots using screenshot.label. For example screenshot.label:desktop

Searching for labels using this filter doesn’t always return a complete set of results from my experience, luckily we can also query for them from images.shodan.io.

SSL Certificates

From my experience, searching for SSL certificate hostnames in Shodan is a great way of identifying hosts based on SSL information. We can do this with the hostname filter in Shodan. For example, we will look for hosts using an SSL certificate containing contoso.com:

We can also combine multiple hostnames together which can help to reduce the number of queries made to Shodan! For example we can hunt for contoso.com and example.com with the following query:

hostname:contoso.com,example.com

We can also look within an SSL Certificate for part of the issuer CN or subject CN. For example, hosts with a certificate issued by test.local

And searching by subject name

HTTP Content

As expected, we can look within the HTML content of pages to find results. This has previously been done with the R1Soft vulnerability found by Huntress in early November 2022. Using their query of http.html:"Server Backup Manager SE" we can see that at the time of writing this post, 3,192 backup appliances remain online – showing that their vulnerability has led to nearly 2,000 backup devices being removed from the internet.

As an example, we can look for other queries which can identify other R1Soft devices. As an example, we could search for the favicon to find other systems which might not include the string “Server Backup Manager SE“. To do this, we can click on this host and click on the Raw Data tab at the top of the page

After digging through the data, we find the hash is -450254253, which we can then hunt for using http.favicon.hash:-450254253, revealing a further 1,000 devices which could well be additional backup servers (Though we would want to further validate these results!)

With this query, we can use the ‘Historical Trend’ tab to show historical data on this query. This shows that the number of devices exposed to the internet has been gradually decreasing since 2018, with a sharp decline since the vulnerability was released

Continuing with the R1Soft theme, the core vulnerability was due to an authentication bypass (CVE-2022-36537) within the ZK framework. We can also search Shodan for sites using ZK with the http.component:zk query. We can see this returns over 6,000 results and includes some R1Soft systems

More Complex Queries

With Shodan we can combine several queries together to perform some complex searches. For this I will start with the R1Soft systems from above. We might be interested in finding which systems could be vulnerable to CVE-2022-36537 within the ZK library, but ignore any R1Soft systems (As they will be obviously patched by now..).

To do this, I will combine the http.component and then ignore any results from the http.favicon.hash query results, which we performed earlier, giving us the following query: http.component:zk -http.favicon.hash:-450254253

Finding Interesting Hosts For A Target

This is where Shodan shows its power – we can search for hosts for a target which have interesting ‘stuff’ related to them. For example, we can combine the hostname filter (To find hosts based on their SSL certificate) and the port filter (To find those with SSH exposed).

Assuming our the internal domain name of our target was ‘domain.local‘, we can find 12 potential hosts with SSH exposed with the query hostname:domain.local port:22.

In a similar vein, I also quite like to perform that search but ignore both port 80 and 443 with -port:80 -port:443. We can also shrink this query by doing -port:80,443 instead!

Using our fictitious target of ‘domain.local‘, this search reveals 53 hosts which have an SSL certificate for domain.local and are exposing what I would consider as non-standard port

Find potentially unmanaged devices

Another useful one is to ignore a ‘range’ of IP addresses (Whether this is via CIDR or an ASN) and then search for your targets name via some means (HTML content, SSL Certificates and so on).

For example, looking for a Microsoft term within the HTML content (http.html:contoso) and ignoring any hosts which are within an ASN which has Microsoft in the name (-org:microsoft). This search is shown below:

Or in a similar vein, we can search for hosts with a certificate subject name containing ‘contoso‘, and ignore any SSL certificates with a hostname containing ‘microsoft.com‘, making a query of: ssl.cert.subject.cn:contoso -hostname:microsoft.com

Tracking Assets Over Time

Another way of using the ‘Historical Trend’ tab is to track individual assets over time by effectively performing a basic historical search. For example, lets assume we want to find all the hosts which have exposed their CLR version via a header. To do this, we will take one of the examples from above and append a query for ‘X-AspNet-Version‘ headers, giving us a current set of 15 devices:

ssl.cert.subject.cn:contoso -hostname:microsoft.com X-AspNet-Version

Now what if we want to see if any other hosts would have met that criteria in the past? We can do that by going to the Historical Trend tab. As we can see below, the number of devices has varied significantly over the previous 5 years:

From here we can click on ‘Facet By’ and select IP to get a list of all the IP addresses which constitute the data in the graph above

Unfortunately we cannot access the hostname value, but we can also access the ssl.cert.subject.cn parameter which might reveal some hostname information

This data might provide a starting point for us to discover which assets have revealed that header.

Summary

Hopefully this post has been of use, below are some other blog posts which I found helpful: