In each circumstances the attackers used the vulnerability to add encrypted recordsdata with the extension .txt which have been then decoded utilizing the Certutil WIndows utility into .jsp recordsdata that served as net shells — backdoor scripts that permit attackers to distant execute instructions on a server. In one of many incidents the attackers created a staging folder the place they dropped a number of utilities: a cookie exporting DLL file that’s a part of Microsoft’s Edge browser, a community useful resource scanner referred to as fscan.exe, a duplicate of the Microsoft Useful resource Compiler, and different executables.
The malicious net shell additionally contained code that tried to decrypt passwords for ColdFusion knowledge sources. ColdFusion saves passwords in encrypted type with a seed worth that was hard-coded in ColdFusion 8, however is exclusive for every set up in later variations.
“A risk actor who has management over the database server can use the values to decrypt the information supply passwords in ColdFusion model 8 or older,” CISA explains. “The sufferer’s servers have been operating a more recent model on the time of compromise; thus, the malicious code did not decrypt passwords utilizing the default hard-coded seed worth for the older variations.”
The attackers behind the second incident appear to have been extra expert and used extra superior reconnaissance ways. They enumerated area trusts by utilizing nltest instructions they usually collected details about native and area administrative accounts by utilizing instructions akin to localgroup, internet consumer, internet consumer /area and ID. Additionally they tried to find community configuration, time logs, and question consumer info.
In response to CISA the attackers tried to repeat and exfiltrate system registry hives akin to HKEY_LOCAL_MACHINE (HKLM) and the Safety Account Supervisor (SAM), however the exercise was detected and blocked. “The SAM Registry file might permit for malicious actors to acquire usernames and reverse engineer passwords; nevertheless, no artifacts have been accessible to verify that the risk actors have been profitable in exfiltrating the SAM Registry hive,” the company mentioned.
The attackers additionally dumped the reminiscence of the native security authority subsystem service (LSASS), which normally comprises NTLM credentials for consumer accounts that have been used on the system, together with disabled credentials which may nonetheless be legitimate on different techniques.
