Security News
Threat actors are hacking Microsoft Exchange servers using ProxyShell and ProxyLogon exploits to distribute malware and bypass detection using stolen internal reply-chain emails. TrendMicro researchers have discovered an interesting tactic used of distributing malicious email to a company's internal users using the victim's compromised Microsoft exchange servers.
The Iranian APT has been exploiting Fortinet vulnerabilities since at least March 2021 and a Microsoft Exchange ProxyShell vulnerability since at least October 2021, according to the alert. In keeping with what CISA described on Wednesday, MSTIC has seen the Iran-linked Phosphorous group - aka a number of names, including Charming Kitten, TA453, APT35, Ajax Security Team, NewsBeef and Newscaster - globally target the Exchange and Fortinet flaws "With the intent of deploying ransomware on vulnerable networks."
"FBI and CISA have observed this Iranian government-sponsored APT group exploit Fortinet vulnerabilities since at least March 2021 and a Microsoft Exchange ProxyShell vulnerability since at least October 2021 to gain initial access to systems in advance of follow-on operations, which include deploying ransomware," CISA said. The Iranian state hackers focus their attacks on US critical infrastructure sectors and Australian organizations.
Microsoft has released security updates as part of its monthly Patch Tuesday release cycle to address 55 vulnerabilities across Windows, Azure, Visual Studio, Windows Hyper-V, and Office, including fixes for two actively exploited zero-day flaws in Excel and Exchange Server that could be abused to take control of an affected system. The most critical of the flaws are CVE-2021-42321 and CVE-2021-42292, each concerning a post-authentication remote code execution flaw in Microsoft Exchange Server and a security bypass vulnerability impacting Microsoft Excel versions 2013-2021 respectively.
Microsoft has released security updates as part of its monthly Patch Tuesday release cycle to address 55 vulnerabilities across Windows, Azure, Visual Studio, Windows Hyper-V, and Office, including fixes for two actively exploited zero-day flaws in Excel and Exchange Server that could be abused to take control of an affected system. The most critical of the flaws are CVE-2021-42321 and CVE-2021-42292, each concerning a post-authentication remote code execution flaw in Microsoft Exchange Server and a security bypass vulnerability impacting Microsoft Excel versions 2013-2021 respectively.
It's a light November 2021 Patch Tuesday from Microsoft: 55 fixed CVEs, of which two are zero-days under active exploitation: CVE-2021-42321, a Microsoft Exchange RCE, and CVE-2021-42292, a Microsoft Excel security feature bypass bug.CVE-2021-42321, the remote code execution vulnerability in Microsoft Exchange Server 2016 and 2019, is due to issues with the validation of command-let arguments.
Microsoft warned admins today to immediately patch a high severity Exchange Server vulnerability that may allow authenticated attackers to execute code remotely on vulnerable servers. The security flaw tracked as CVE-2021-42321 impacts Exchange Server 2016 and Exchange Server 2019, and it is caused by improper validation of cmdlet arguments according to Redmond's security advisory.
A new threat actor is hacking Microsoft Exchange servers and breaching corporate networks using the ProxyShell vulnerability to deploy the Babuk Ransomware. The ProxyShell attacks against vulnerable Microsoft Exchange servers started several months ago, with LockFile and Conti being among the first ransomware groups to exploit them.
A new bad actor called Tortilla is running the campaign, and most affected users are in the U.S. Cisco Talos has a warning out for U.S. companies about a new variant of the Babuk ransomware. Security researchers Chetan Raghuprasad, Vanja Svajcer and Caitlin Huey describe the new threat in a Talos Intelligence blog post.
A new-ish threat actor sometimes known as "Tortilla" is launching a fresh round of ProxyShell attacks on Microsoft Exchange servers, this time with the aim of inflicting vulnerable servers with variants of the Babuk ransomware. ProxyShell is a name given to an attack that chains a trio of vulnerabilities together, to enable unauthenticated attackers to perform remote code execution and to snag plaintext passwords.