Brazilian Trojan in PNG image

[sman]

- Quote

Security researchers at Kaspersky Lab have discovered a new piece of malware that uses a PNG (Portable Network Graphics) image to hide malicious code.

The malware is distributed by email in a clean PDF, which includes a link to a .zip file that contains the malicious image, along with other files. This type of attack is not new, but is similar to previously observed attacks where cybercriminals distribute .exe or .zip files that contain a .pdf extension in the filename.

While the attack technique is not new, the delivery method is, revealing that bad actors are doing their best to find new ways to ensure their malicious code goes undetected by anti-virus products. 

Last year, information-stealing malware Stegoloader, which caused havoc among North American healthcare organizations, was also observed using a PNG image file to hide its main module. The image file was downloaded using a hardcoded URL in the initial payload and was automatically decompressed and decrypted to execute the malware and infect the compromised computer.

In this new scenario, Kaspersky's Thiago Marques explains that attackers have moved beyond simple phishing attacks and attempted to hide the malicious payload in encrypted files that have a known file format, to avoid raising user suspicion. 

- Unquote

read on in http://www.securityweek.com/brazilian-trojan-conceals-malicious-code-png-image

[David H. Lipman]

Steganography is not new.

[sman]

But why KIS should draw attention to it now. since delivery method seems to have evolved to evade detection by AV's , a vulnerability till this is properly plugged..

[David H. Lipman]

Because Brazil is a target of big time monetary theft ( Banload ) and the malware is increasing complexity.

I'm sorry but unlike others, I don't discuss the technical aspects in public ( even if others may have already done so ).

[sman]

When 'Safe Hex' is the only line of defense, against the latest form of attack, and advocated by a AV of the standing of KIS, another blow to AV's protection capabilities, upping user's concerns on protection for a better/lasting solution..

[David H. Lipman]

" against the latest form of attack "

Files using steganography are not an attack vector.  The use of the concept is nothing but a tool of a process.  It is used for file survival and to increase the life of bancos trojans waiting for deployment.  Malware encased in graphic files are rendered harmless.  It takes a program to extract the malicious EXE from said graphic.  It is the same as if an EXE is placed in an Archive file in that once it is in an archive file the EXE is safe to handle.  It is a trick to hide in plain site.

 

[sman]

Yes..Av's will not report anything unusual and user's will be in false sense of security, until some harmless action/activity like "iexplore.exe" triggers the malicious code.. In fact, as per KIS this Banking trojan attacks have hit users even outside of Brazil, in US, Mexico, Spain etc. A real worry indeed..

[David H. Lipman]

Unless a malicious binary masquerades as IEXPLORE.EXE ( and any file can be named anything ) it would not trigger anything.  It takes an external program to extract or do a mathematical function, such as XOR, on the file to obtain the malware or extract the malware.  Even then there may be another step.  Again, I won't go into details.

The years of creating malware for "Bragging Rights" are over and the was the era of when the preponderance of malware were indeed viruses.  It is all about financial gain.  Viruses are now relegated to the fringe and minority where trojans account for the vast plethora of malware.

 

[sman]

:iexplore.exe was what the article referred to, which is " it ensures that the malicious code is executed in the context of another process, in this case iexplore.exe, while also making it difficult to detect the nefarious operation.", giving the impression that an innocous normal activity can be a trigger to the malicious code..

 

 

 

[David H. Lipman]

I'm sorry you don't get what is written in the article.  You think IEXPLORE.EXE is a trigger but miss that it is the end point.

Quote

"The researchers identified the function that loads the PNG files to the memory and discovered that it is also responsible for decrypting and executing the extracted binary ".

Which goes back to what I wrote earlier and what I have seen.

Once the payload is obtained and applied, it may usurp legitimate functions for their benefit via code injection or it may try to masquerade as a legitimate process.

 

 

 

[sman]

Tks for clarifying ..So, VBInject or VBcrypt and then IEXPLORE.EXE ..But it is the question of protection, as the article gives no hope and a point of no return once the link is clicked.. which is what is chilling to note..

[David H. Lipman]

Nothing has changed.  The same that was true before the article is the same after it.

It is only highlighting an increased level of complexity the malicious actors are taking to perform their dirty deeds.

 

[sman]

Is there a way out to stay protected post mis-adventure with the link/attachment?

[David H. Lipman]

I do not understand the question and how it relates to this FYI article on Brazilian Banload trojan implementations and the subsequent discussion.

[sman]

All the effort is to know the real "impact" to the user,, Whether there is protection against the "threat" or not? 

[David H. Lipman]

It is not a "threat".  It is a modus operandi.  The article is a FYI.

[sman]

OK ..It;s a FYI article with the purpose to alert the user's to the change in modus operandi but silent about protection, which every user would like to know, since it is spreading beyond Brazil and far?

[David H. Lipman]

I give up...