4.3.x does not scan compressed archives (7z, zip, rar, etc.)?

[hexaae]

Every time I try to manually scan a compressed archive in ZIP, RAR, 7Z etc. formats I see the scan lasts just a moment and the report always says:
Scanned files: 1

even though the archive contains many files... It looks like it's not working as expected even though I've set to scan archives in the MB Settings:

E.g. of a ZIP scan report:

Malwarebytes
www.malwarebytes.com

-Dettagli log-
Data scansione: 15/02/21
Ora scansione: 22:01
File di log: ecc2bd06-6fd0-11eb-a486-0c9d92a56fd0.json

-Informazioni software-
Versione: 4.3.0.98
Versione componenti: 1.0.1157
Aggiorna versione pacchetto: 1.0.37165
Licenza: Premium

-Informazioni sistema-
SO: Windows 10 (Build 19041.804)
CPU: x64
File system: NTFS
Utente: LAPTOP-DVK1QFAS\Luca

-Riepilogo scansione-
Tipo di scansione: Scansione personalizzata
Scansione avviata da: Manuale
Risultati: Completata
Elementi analizzati: 1
Minacce rilevate: 0
Minacce messe in quarantena: 0
Tempo impiegato: 0 min, 2 sec

-Opzioni di scansione-
Memoria: Disattivata
Esecuzioni automatiche: Disattivata
File system: Attivata
Archivi compressi: Attivata
Rootkit: Disattivata
Analisi euristica: Attivata
PUP: Rilevare
PUM: Rilevare

-Dettagli scansione-
Processo: 0
(Nessun elemento nocivo rilevato)

Modulo: 0
(Nessun elemento nocivo rilevato)

Chiave di registro: 0
(Nessun elemento nocivo rilevato)

Valore di registro: 0
(Nessun elemento nocivo rilevato)

Dati di registro: 0
(Nessun elemento nocivo rilevato)

Flusso di dati: 0
(Nessun elemento nocivo rilevato)

Cartella: 0
(Nessun elemento nocivo rilevato)

File: 0
(Nessun elemento nocivo rilevato)

Settore fisico: 0
(Nessun elemento nocivo rilevato)

WMI: 0
(Nessun elemento nocivo rilevato)


(end)

 

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[Porthos]

I see the exact same thing.

[AdvancedSetup]

I'm not sure if we ever did list them or not, or if we simply listed the one archive file scanned. I've asked the internal team but it's a Holiday here in the USA

From our Support documentation:

Scan within archives: If this box is checked, archive file types such as zip, 7z, rar, cab and msi are scanned up to two levels deep. Password protected archives cannot be tested.

https://support.malwarebytes.com/hc/en-us/articles/360038984773-Scan-types-in-Malwarebytes-for-Windows

 

 

[David H. Lipman]

I believe that when scanning an Archive file, MBAM will go only X layers deep and MBAM will not count files in the Archive and just display a scan of 1 file representing the Archive [ ZIP, RAR, 7zip, CAB and MSI ].

Edited February 16, 2021 by David H. Lipman
Edited for content, clarity, spelling and grammar

[AdvancedSetup]

I thought this was a logging issue. It appears that archive scanning is not working as expected. I have reported this to our internal team for review.

Scanning an archive that has infected files within the archive shows no infection. Extracting the same files and context scanning shows there are infected files.

Thank you @Porthos for providing a safe test file to confirm this behavior and thank you @hexaae for reporting

 

[AdvancedSetup]

Hello @hexaae

I have reviewed with our Team and we actually just report the archive as 1 file. We don't log the names of any specific files in the archive when scanning.

The program is working correctly as designed

Thank you

 

[hexaae]

19 hours ago, AdvancedSetup said:

Scanning an archive that has infected files within the archive shows no infection. Extracting the same files and context scanning shows there are infected files.

 

What about this... ?

[AdvancedSetup]

If an archive is is too deep in layers it won't be scanned. If you have files that are large or complex then it is best to extract them and scan the folder.

 

 

[exile360]

Also keep in mind that in order to actually execute/infect a system, malware within an archive would first need to be extracted (double-clicking a file directly from within the archive causes that file to be extracted to a temp folder before it can be launched into memory), and once that occurs, Malwarebytes' real-time protection should detect the file it and quarantine it if it is a threat.

If using the free version, I'd recommend extracting the archive's contents to their own folder first, then scanning the folder with Malwarebytes to ensure all of the contents are clean, that way you can then either delete the archive, or remove the infected items from the archive and rebuild it without any threats inside.