According to reports published by Microsoft and Akamai, cybercriminals are targeting SolarWinds devices with the Log4Shell vulnerability, and ZyXEL is known to use the Log4j library in their software.
Attacks have been reported on SolarWinds and ZyXEL devices using the log4j library, according to Microsoft and Akamai reports. CVE-2021-35247 has been assigned to the vulnerability, which has been paired with a zero-day in the SolarWinds Serv-U file-sharing service.
According to Microsoft's Threat Intelligence Center (MSTIC), the SolarWinds vulnerability, dubbed CVE-2021-35247, is a data validation hole that might allow attackers to compose a query based on some data and send it across the network without sanitizing.
Jonathan Bar-Or, a Microsoft security researcher, is credited with identifying the flaw, which affects Serv-U versions 15.2.5 and earlier. In Serv-U version 15.3, SolarWinds patched the vulnerability. "A closer look helped discover the feed Serv-U data and it generates an LDAP query using the user unsanitized input!" he claimed. Not only might this be included in log4j attacks but it also is used for LDAP injection.
SolarWinds claimed in its advisory, the Serv-U online log-in screen for LDAP authentication is permitting symbols that are not appropriately sanitized and it had modified the input method "to do further validation and sanitization." The attacker cannot log in to Serv-U, according to a SolarWinds official, and the Microsoft researcher is referring to failed attempts because Serv-U doesn't use Log4J code.
The unverified remote code execution (RCE) vulnerability in Log4j – identified as CVE-2021-44228 – has also been repurposed to infect and assist in the dissemination of malware used for the Mirai botnet by targeting Zyxel networking equipment, according to Akamai researchers. When researchers intended to access the Java payload class, the LDAP server in which the exploit was located was no longer active. It's claimed that Zyxel was particularly singled out since published an article claiming to have been hit by the log4j flaw.
The scenario surrounding the Log4Shell breach has remained unchanged since last month, and threat actors looking to get access to corporate networks continue to target and exploit the vulnerability. Threat actors including ransomware gangs, nation-state cyber-espionage groups, crypto-mining gangs, initial access brokers, and DDoS botnets have all been reported to have exploited the vulnerability in the past.
Although the Apache Software Foundation has issued patches for the Log4j library, threats against applications using it are likely to persist because not all of these apps have published a set of security updates, abandoning many systems vulnerable and creating a breeding soil for exploitation that will last for years.
