Love Letter

[Masonjar13]

While this is a relatively old, VBS based virus, yesterday, I had to clean a computer that got infected by it off an old HDD. MBAM (chameleon) was the first thing I ran, of course, but it didn't find it as a virus. Does MBAM just not check VBS files? I can post it if you guys can't get it yourself, but I'll have to get it off that drive, which may be difficult (IDE, no native IDE connectors).

Infected PC was running Windows 10. UAC saved it from entering the registry or system files, but all .jpg/.jpeg files were lost. .mp3's were "impersonated" (marked the original mp3's as hidden and copied it's VBS with the same name to the same directory), which was easily solved with a bit of my own code. It certainly hasn't aged well, but is still quite a nuisance and I would greatly appreciate it being added to the definitions.

[David H. Lipman]

MBAM is not an anti virus application and does not replace an an anti virus application.  MBAM is an adjunct, complimentary, anti malware application.
 
In its role as a adjunct, complimentary, anti malware application it has limitations in aspects that the anti virus application performs in its role.
 
MBAM does not target script files. That means MBAM will not target; JS, JSE, PY, .HTML, HTA, VBS, VBE, .CLASS, SWF, SQL, BAT, CMD, PDF, PHP, WSF, etc.
It also does not target document files such as; PDF, DOC, DOCx, DOCm, XLS, XLSx, PPT, PPS, ODF, RTF, etc.
It also does not target media files;  MP3, WMV, JPG, GIF, etc.

Until MBAM, v1.75, MBAM could not access files in archives but with v1.75 came that ability so it can unarchive a Java Jar (which is a PKZip file) but it won't target the .CLASS files within. Same goes with CHM files (which is a PKZip file) but it doesn't target the HTML files within. MBAM v1.75 specifically will deal with; ZIP, RAR, 7z, CAB and MSI for archives. And self-Extracting; ZIP, 7z, RAR and NSIS executables (aka; SFX files).

MBAM specifically targets binaries that start with the first two characters being; MZ
They can be; EXE, CPL, SYS, DLL, SCR and OCX. Any of these files types can be renamed to be anything such as;  TXT, JPG, CMD and BAT and they will still be targeted just as long as the binary starts with 'MZ'.
 
MBAM targets mainly non-viral malware.  The exception being a virus dropper ( a malware file that drops a virus and starts a virus infection but is not infected with the virus ) and worms ( such as Internet worms and AutoRun worms ).
 
MBAM is incapable of removing malicious code that has been prepended, appended or cavity injected into a legitimate file.  That means if a file infecting virus infects a legitimate file MBAM will be unable to remove the malicious code.  An anti virus application should be able to remove malicious code from an infected file and hopefully bring it back to its preinfected state.  Which may or may not return the file to its original, non infected, checksum value.
 
A file infecting virus will prepend, append or cavity inject malicious code into a legitimate file.  Once infected, that infected file can further the infection by infecting other legitimate files.
 
On the other hand there are trojans that will prepend, append or cavity inject malicious code into a legitimate file.   However that file can not infect other files.  The infection stops with that targeted file.  These files are either deemed to be "trojanized" or "patched".  Since MBAM can not remove the added malicious code, at best MBAM will try to replace the trojanized file with a legitimate, unaltered, file.
 
Where a traditional anti virus application is weak, MBAM is strong.  Today's malware is much more complex than 10 years ago.  When we saw the Melissa virus ( I-Worm via SMTP  ), Lovsan/Blaster worm (  I-Worm via RPC/RPCSS @ TCP port 135 ) etc, they were distributed for the effect, damage and bragging rights.  Today's malware is more sophisticated in that it is "all about the money".  Malicious actors use malware to profit from.  Either by stealing, distribution affiliation revenue, data exfiltration, personal identification impersonation, etc.  To effect that the malicious actors don't want the victim to know that their system was compromised or they are so blatant about it by generating advertisements,  Yesterday's malware was simple and less obtrusive.  Today's malware is very intrusive and makes numerous modifications to the Operating System.  Those numerous modifications to the Operating System is where the traditional anti virus application does poorly and where MBAM specializes.
 
MBAM is not a historical anti malware solution.  That means it will not target old malware.  It's intent is to target 0-Day malware.  Malware that is infecting computers Today with malware found in-the-wild, Today.  That means that something like the BugBear which infected years ago will not be targeted by MBAM.  Malwarebytes will actually cull their signature database for malware that is no longer seen in-the-wild Today.   It is why Malwarebytes requests samples that are submitted for detection consideration be no older than 3 months old.

 

 

[Masonjar13]

Noted, thank you for the response.

[David H. Lipman]

YW

 

Is there anything else ?

 

[Masonjar13]

Yes: is there any portable AV software you would recommend? For scanning, similar to MBAM chameleon, not for integration.

[David H. Lipman]

Chameleon isn't a portable MBAM.  Chameleon is the name of the technology Malwarebytes applies to thwart the self preservation techniques that malware may use.

I don't have a suggestion for a portable AV.  Sorry.

 

[Masonjar13]

18 minutes ago, David H. Lipman said:

Chameleon isn't a portable MBAM.  Chameleon is the name of the technology Malwarebytes applies to thwart the self preservation techniques that malware may use.

.. I knew that already, I don't know why I said that. Never mind. Off day, I suppose.

Thank you for the help/information, feel free to close the thread.

[AdvancedSetup]

Since this issue is resolved I will close the thread to prevent others from posting here. If you need assistance please start your own topic and someone will be happy to assist you.