Thursday, November 6, 2014

WireLurker, a shock in Apple World.

I am not used to write "Malware centric" posts, contrary I do love to focalize my writing on specific techniques used by Malware to infect systems and/or to evade analysis. However today,  I want to stamp in my digital diary WireLurker since I see a "paradigm shift" on it. I find it a super fascinating peace of code where motivations are still unclear. WireLurker has been firstly analyzed by Unit42 (Palo Alto Networks) and suddenly became a quite spread news. It targets OSX and iOS devices (one of the first Malware entirely written for Apple platforms). WireLurker owns the following specif characteristics:
  • It is only the second known malware family that attacks iOS devices through OS X via USB 
  • It is the first malware to automate generation of malicious iOS applications, through binary file replacement 
  • It is the first known malware that can infect installed iOS applications similar to a traditional virus 
  • It is the first in-the-wild malware to install third-party applications on non-jailbroken iOS devices through enterprise provisioning 
PaloAlto networks writes:
Of known malware families distributed through trojanized / repackaged OS X applications, it is the biggest in scale we have ever seen.  .
 WireLurker was used to trojanize 467 OS X applications on the Maiyadi App Store, a third-party Mac application store in China. In the past six months, these 467 infected applications were downloaded over 356,104 times and may have impacted hundreds of thousands of users. The following image shows the complete infection workflow.

Complete infection workflow: From PaloAlto unit42 report

Fascinating how simple is the thechnique used by the Malware writers to Trojanize a legitime APP.  Please substitute %@ with real paths to make sense on it.

Trojanize script used by WireLurker. From PaloAlto unit42 report
Once the "Trojanized App" has been saved on the infected machine, WireLurker builds its own "empire" by downloading applications, updating itslef and hiding files into folders spread on the file system. The following image  shows the amount of dropped, created, deleted file into the targeted machine.

From PaloAlto unit42 report
Even more fascinating the way WireLurker get persistence on the device. Generally speaking WireLurker runs as a background process, waiting for iOS devices to infect over USB connection, this represents a quite simple process, however it adopts multiple redundancy methods to guarantee its own presence such as:
  • It does not check if the device is already infected, each time it executes malicious code. 
    • This is actually a weak point. Detectors might exploit this behavior to identify it.
    • It is not really "silent" adopting this "forcing method"
  • WireLurker initialization and update scripts create and load launch daemons, ensuring persistence after reboot.
    • Pretty simple approach if compared to complex Bootkit Malware who does not initialized a direct daemon.
  • It invokes the following launchctl 
From PaloAlto unit42 report

Comunication to Command and Control happens by using a Data Encryption Standard (DES) with Cryptographic Message Syntax Standard (PKCS7) padding. Researcher from PaloAlto Networks figured out that for each piece of TCP data WireLurker receives or sends, the first 10 bytes of the data are used to generate a session key. The session key is then combined with a fixed string, “dksyel”, to generate a decryption key. Remaining bytes of the data are encrypted data that has also been encoded using Base64. From here the analysis is quite usual.

Quoting the unit42 report:
The ultimate goal of the WireLurker attacks is not completely clear. The functionality and infrastructure allows the attacker to collect significant amounts of information from a large number of Chinese iOS and Mac OS systems, but none of the information points to a specific motive. As infected devices regularly request updates from the attackers command and control server, new features or applications could be installed at any time. It’s clear the tool set is still undergoing active development and we believe WireLurker has not yet revealed its full functionality.
It is a quite weird behavior. Right now I do not have enough elements to understand the goal of such a targeted attack. Having a general information about Apple device owners seems to me a quite original target per se. For shure the security perspective for Apple users have been deeply changed.

Monday, October 13, 2014

The Most Famous Malwares in APTA

During my talks and during my daily working life people asks me about the most interesting Malware used to perform Advanced Persistent Targeted Attacks (APTA). So I decided to give my personal answer in this post, beeing concious that things would change pretty soon.

Lets start with Stuxnet, maybe one of the most known APTA known in the history, also responsible to giving pubblic begin to the cyber-espionage.

Stuxnet is a computer worm that was discovered in June 2010. It was designed to attack industrial Programmable Logic Controllers or PLCs. PLCs allow the automation of electromechanical processes such as those used to control machinery on factory assembly lines, amusement rides, or centrifuges for separating nuclear material. Exploiting four zero-day flaws, Stuxnet functions by targeting machines using the Microsoft Windows operating system and networks, then seeking out Siemens Step7 software. Stuxnet reportedly compromised Iranian PLCs, collecting information on industrial systems and causing the fast-spinning centrifuges to tear themselves apart. Stuxnet’s design and architecture are not domain-specific and it could be tailored as a platform for attacking modern SCADA and PLC systems (e.g. in the automobile or power plants), the majority of which reside in Europe, Japan and the US.Stuxnet reportedly ruined almost one-fifth of Iran's nuclear centrifuges.
From TrendMicro Report

Stuxnet has three modules:
  1. a worm that executes all routines related to the main payload of the attack; 
  2. a link file that automatically executes the propagated copies of the worm; and 
  3. a rootkit component responsible for hiding all malicious files and processes, preventing detection of the presence of Stuxnet. 
Stuxnet was able to exploit the following vulnearbilities: CVE-2010-2568, CVE-2008-4250, CVE-2010-2729 and CVE-2010-277. It mainly got started from USB sticks and spread over PCs throught vulns. What it did was to substitute a Siemens DLL getting control of Siemens SCADA systems. A later updated version was also able to exploit the CVE-2010-2772being able to read and write directly on Siemens SCADA database (.DBI).

Another great example is Flame.

also known as Flamer, sKyWIper and Skywiper, is modular computer malware discovered in 2012 that attacks computers running the Microsoft Windows operating system. The program is being used for targeted cyber espionage in Middle Eastern countries.Flame can spread to other systems over a local network (LAN) or via USB stick. It can record audio, screenshots, keyboard activity and network traffic. The program also records Skype conversations and can turn infected computers into Bluetooth beacons which attempt to download contact information from nearby Bluetooth-enabled devices. This data, along with locally stored documents, is sent on to one of several command and control servers that are scattered around the world. The program then awaits further instructions from these servers.

SecureList Thread

Flame was actualy one of the most complext computer malware ever. Super "heavy" it comes within database server, very uncommon virtual machines (lua), file sharing, specific "red protocols", gzlibs, encryption libs and so on.. A great client analysis can be found here. My favorite Server analysis can be found here.

Duqu is another big name in the APTA's world.

Duqu malware is a variety of software components that together provide services to the attackers. Currently this includes information stealing capabilities and in the background, kernel drivers and injection tools. Part of this malware is written in unknown high level programming language, dubbed "Duqu framework". It is not C++, Python, Ada, Lua and many other checked languages. However, recent evidence suggests that Duqu may have been written in Object Oriented C (OO C) and compiled in Microsoft Visual Studio 2008.

Duqu main components and modules from this report

The  dropper file recovered and disclosed by CrySyS Lab uses a Microsoft Word (.doc) document which exploits the Win32k TrueType font parsing engine and allows execution (btw, a nice article on that vulnerability is here). The Duqu dropper relates to font embedding, and thus relates to the workaround to restrict access to T2EMBED.DLL, which is a TrueType font parsing engine if the patch released by Microsoft in December, 2011 is not yet installed. Microsoft identifier for the threat is MS11-087. Duqu has tons of similarity with Stuxnet, common code have been prooved.

A most recent attack to spy diplomats'name is Turla.

Turla has been used for classic espionage-type operations for at least four years. Because of the targets chosen and the advanced nature of the malware used, Symantec believes that a state-sponsored group was behind these attacks. Turla provides the attacker with powerful spying capabilities. Configured to start every time a computer starts, once the user opens a Web browser it opens a back door that enables communication with the attackers. Through this back door, the attackers can copy files from the infected computer, connect to servers, delete files, and load and execute other forms of malware, among other capabilities. The group behind Turla uses spear phishing emails and watering hole attacks to infect victims. Some of the spear phishing emails purported to come from a military attaché at a Middle Eastern embassy and had an attachment masquerading as the minutes of meetings. Opening the attachment resulted in Trojan.Wipbot being dropped on to the victim’s computer. It is believed that Wipbot may be the delivery mechanism for Turla as they share several similarities in code and structure.

How Turla is pread, from here.
 Turla malware has been used to to facilitate watering hole attacks since 2012, its most advanced feature was to be totally FUD for many years. Later on it has been used to deliver Wipbot, a famous malware used to gather further information about the infected computer. If the attackers deemed the victim of interest, it appears likely that a second back door (Trojan.Turla) with far greater capabilities was downloaded on to the victim’s computer.

In 2012 Gauss Malware hit the Middle east community.

Like Flame and Duqu, the propagation of Gauss seems to be controlled in order to maintain stealth and avoid detection. Gauss is a complex, nation-state sponsored cyber-espionage toolkit designed to steal sensitive data, with a specific focus on browser passwords, online banking account credentials, cookies, and specific configurations of infected machines. The online banking Trojan functionality found in Gauss is a unique characteristic that was not found in any previously known cyber-weapons. Kaspersky write: “The payload is run by infected USB sticks and is designed to surgically target a certain system (or systems) which have a specific program installed. One can only speculate on the purpose of this mysterious payload.” The malware copies itself onto any clean USB inserted into an infected PC, then collects data if inserted into another machine, before uploading the stolen data when reinserted into a Gauss-infected machine.
From kaspersky labs

HiKit is one of the most advanced RootKit used in APTA.

Entirely described by Mandiant (Here and Here) the “Hikit” Malware uses an interesting covert mechanism for command and control. It installs itself as a virtual network adapter layered between the NIC and overlying protocol drivers. This allows it to covertly monitor incoming packets, intercept command and control data as it enters the network stack, and then spawn user-mode threads to parse them accordingly.

(Extracted from Mandiant Analysis)
HiKit writes to the system  two main files :
  1. C:\WINDOWS\system32\wbem\oci.dll 
  2. C:\WINDOWS\system32\drivers\W7fw.sys 
“oci.dll” extracts a number of files from its resources section:
  1. The rootkit driver “W7fw.sys” 
  2.  Several requisite .INF and .CAT files for the driver 
  3. A digital certificate “GlobalSign.cer”, along with a copy of Microsoft’s Certificate Manager tool “certmgr.exe” 
The attacker self-generated “GlobalSign.cer” to masquerade a legitimate certificate issued by GlobalSign – it was not stolen nor legitimate. The malware proceeds to use “certmgr.exe” to install the certificate to the local trust store as a root CA and Trusted Publisher using the following two commands: 
  • certmgr.exe -add GlobalSign.cer -c -s -r localMachine Root
  • certmgr.exe -add GlobalSign.cer -c -s -r localMachineTrustedPublisher 
It then attempts to disable driver signing verification by tampering with several registry keys. Finally, it completes the driver installation process and checks that it is properly loaded.
After the installation and the infection procedure HiKit starts to grab usernames and passwords of Window Locals and Windowns Remote accesses as well as well-known profiles of internet banking and famous serives. It does provide a modular backdoor to manage the malware and the hosting system 

I am aware those are only some of the most famous Malware used in APTA, I am aware this little "list" will change over time as well, but as now, I believe those Malware are the most remarkable in APTA.

Wednesday, September 24, 2014

Bash Vulnearbility: CVE-2014-6271

Test if you are vulnerable

Nothing really to add here. It makes me just thinking.... those things still happens (thxG). More here, here, here, here and here

UPDATE (click to enlarge):
From PasteBin (here)
  No Way... Wondering of many triggering vector would be out there


After some days from the original 6271, more than 5 vulnerabilities have been found on the same "way".  My favorite place to stay up-to-date on this topic is that Repository.
If you are still wondering what are the real risks for your company, here some simple examples from (here).

Find out your vulnerable cgi. Get it, and learn from the results...

As simple is a curl, remove everything you want (this is freaking scary).

And then be sure everything went as you whished.

Are you wondering.... if I could....  , ... , yes you can !

And, yes.. this vulnerability is "wormable", it might be used for spreading worms.

Wednesday, September 10, 2014

Nice Way To Evade Dynamic Analysis

One of the most important rules in building dynamic analysis environments is to avoid internet connection by the "potential malicious code". Indeed the "potential malicious code" would try to exploit the analysis system per se if an internet connection is available. To respect this basic rule, when a sandboxed code tries to open an internet page, the sandbox environment sends back a static 200 code, letting the "potential malicious code" compare the received page to the needed one. At such point the analysis system might try to "taint" and/or to apply its own detection mechanisms. 

A smart way to detect if a code is sandboxed or not is to try to reach out an unreachable internet site. If the code reads back 200 means the malicious code has been sandboxed since the malicious code is trying to reach an unreachable page. Following a simple python example.

Python2.7 Example

Following a simple JavaExample of the aforementioned technique.

A Java Example
Another tipycal example written in C

C esample
That trick has been known since 2012. Have a nice evasion.

Sunday, July 27, 2014

Cyber Intelligence abusing Internet Explorer to perform Targeted Attacks

A "mandatory" step to achieve a complete and successful targeted attack is the so called: "Cyber Intelligence Phase". By definition every targeted attack owns at leeast one specific characteristic which makes it perfectly fit for a given target. As you might want agree, one of the most important activities on develping a targeted attack is to exactly know what's running on the target system. The activity which takes care of "discovering" what's running on a given system is often called Cyber Intelligence (many of you on the Cyber Intelligence field might know a little bit different definition... but this is not the point). I wont write, in this quick and dirty blog post,  about cyber intelligence, indeed I want to point you out simple techniques to perform a target enumeration by using Internet Explorer. 

One of the most used techniques to perform Cyber Intelligence through Iinternet Explorer (IE) is the "abusing of resources" (res://) calls. This techniques afflicts IE from 6. to 8. It has been widely discussed in many online sites (for example: here, here, here and here). The technique is based on the assumption that IE blocks access to local file system trhough the "file://" call, but let the "res://" call to have access to image resources on file system. To exploit this IE's behavior the attacker might look at specific executables holding (as resource)  specific images. The res abuse://  has been used as Cyber Intelligent Weapon in serveral attacks including the "waterhole campagin afffecting a Thailand NGO" as posted here. The aforementioned behavior could be exploited as follows:

From AlienVault Article
The resList contains the list of executables files used to detect AntiVirus Software. Following a simple example taken from a real case. A similar code was found into Skipot too...

From AlienVault Article
Another used technique to map software into a target host sees its implementation through the Microsoft XMLDOM ActiveX Info disclosure vulnerability. This vulnerability has been videly discussed as well (here, here, and here). Basically Microsoft.XMLDOM is an ActiveX control that can run in Internet Explorer without requiring any prompting to the user. This object contains methods that can leak information about a computer system to the operator of a website. By looking at error codes provided by the XMLDOM ActiveX control, an attacker can check for the presence of local drive letters, directory names, files, as well as internal network addresses or websites. It is confirmed that this issue affects Internet Explorer versions 6 through 11 running on Microsoft Windows through version 8.1. The following code shows an example of the implementation of such a vulnerability. It looks for the presence of specific files into the target system.

Implementation of XMLDOM ActiveX vulns
 Following on this way attackers might use more XMLDOM vulnerabilities such as CVE-2014-0322 in which Microsoft Internet Explorer 9 and 10 allows remote attackers to execute arbitrary code via vectors involving crafted JavaScript code, CMarkup, and the "onpropertychange" attribute of a script element, as exploited in the wild in January and February 2014. MSF exploits are available out there. As WebSense discussed on his Security Blog Post attackers used the described technique to identify the Microsoft EMET presence on the target system. The same technique was found into Angler Exploit Kit and later on Goon and Cool Exploit Kits too.

Cyber Intelligence, is one of the most fascinating field. It does nothing bad per se, it simply offers detailed infos to next "phases". As always happens such infos could be used by legitim systems as well as by attacker' systems. As you problably have learned in the past years... whatch out what you browse  !

Tuesday, July 1, 2014

OpenSSL CCS Attack

As you might see from my posts frequency, last months have been pretty busy to me. My hacking team and I are working really hard and we are achieving incredibly results which makes me happy but really busy as well. OpenSSL CCS Attack (CVE-2014-0224) is almost one month old and not super interesting to be exploited so far, but since we got a great experience on that specific vulnerability I decided to "fix-it" on my memories in the following way.

CVE-2014-0224 bug exists since the very first OpenSSL release and this makes (at least to me) the whole story very fascinating. The issue basically happens because OpenSSL inappropriately accepts the ChangeCipherSpec (CCS) during a handshake. The following picture shows the correct way to implement a full protocol handshake.

The bug finds its own start if If a ChangeCipherSpec message is injected after the ServerHello but before the master secret has been generated  (ClientKeyExchange). At this point ssl3_do_change_cipher_spec generates the keys pair and the expected Finished hash for the handshake with an empty master secret (implementation bug). Moreover, the keys pair will be latched because further ChangeCipherSpec messages regenerate the expected Finished hash, but not new keys anymore. The following image shows the injection time frame.

The buggy code is the following one (the red numbers follow the above description):

int ssl3_do_change_cipher_spec(SSL *s)
 int i;
 const char *sender;
 int slen;

 if (s->state & SSL_ST_ACCEPT)

 if (s->s3->tmp.key_block == NULL)1
  if (s->session == NULL)
   /* might happen if dtls1_read_bytes() calls this */
   return (0);

  if (!s->method->ssl3_enc->setup_key_block(s)) return(0); 2

 if (!s->method->ssl3_enc->change_cipher_state(s,i))

 /* we have to record the message digest at
  * this point so we can get it before we read
  * the finished message */
 if (s->state & SSL_ST_CONNECT)

 i = s->method->ssl3_enc->final_finish_mac(s,
  sender,slen,s->s3->tmp.peer_finish_md); 3
 if (i == 0)
  return 0;
 s->s3->tmp.peer_finish_md_len = i;


Fortunately a patch is available here and a simple go tool to check the bug presence is here. For having more detailed infos, please visit (this post, and the original post).

Friday, May 16, 2014

MalControl Video

After the big success obtained through MalControl open source software, people asked me to record a simple video to show how it's supposed to work. I did use screencast this time.

This short quick'n dirty video shows how MalControl is supposed working. Please refer to the original GitHub page ( for every needs, tickets, request and so on. If you want to add your scraper and/or new frontend features please email me, every support is welcome.