Security experts at Trend Micro have spotted a new cyber espionage campaign that has been active for at least two months and that is targeting Russian-speaking enterprises delivering a new Windows-based backdoor, Trend Micro warns.
The hackers leverage on many exploits and Windows components to run malicious scripts to avoid detection. The last sample associated with this attack was uploaded to VirusTotal on June 6, 2017 and experts at Trend Micro observed five spam campaigns running from June 23 to July 27, 2017.
Hackers are targeting financial institutions and mining firms with different spear phishing messages.
The phishing messages are designed to appear as if they were sent from sales and billing departments and contain a weaponized Rich Text Format (RTF) file that exploits the CVE-2017-0199 flaw in Microsoft Office’s Windows Object Linking and Embedding (OLE) interface.
“The exploit code downloads what is supposedly an XLS file from hxxps://wecloud[.]biz/m11[.]xls. This domain, to which all of the URLs used by this attack point to, is controlled by the attacker and was registered in early July.” states the analysis publiahed by Trend Micro.
The DLL calls is used to power a Squiblydoo attack that leverages the Regsvr32 (Microsoft Register Server) to bypass restrictions on running scripts and evade application whitelisting protections such as AppLocker.
“This particular command uses the Regsvr32 (Microsoft Register Server) command-line utility, which is normally used to register and unregister OLE controls in the Windows registry, including DLL files. This attack method is also known as Squiblydoo—Regsvr32 is abused to bypass restrictions on running scripts.” continues the analysis. “It also means evading application whitelisting protections such as AppLocker. While Squiblydoo is already a known attack vector, this is the first time we’ve seen it combined with odbcconf.exe.”
In May, experts at FireEye spotted a new APT group that was targeting Vietnamese interests around the globe, the hackers leveraged the Squiblydoo technique to enable the download of a backdoor from APT32 infrastructure.
Next, the real backdoor is downloaded and executed, it is an XML file that is downloaded from the domain wecloud[.]biz. Also in this case, it is executed exploiting the same Regsvr32-abusing Squiblydoo attack technique.
” reads the analysis.
Experts noticed that even if the attack chain appears complex, it starts leveraging a Microsoft Office exploit. The best defense still consists in patching and keeping software up-to-date.
(Security Affairs – backdoor, Squiblydoo)