Wrangling the May 2022 Patch Tuesday
Microsoft recently released security updates for over 70 vulnerabilities, including 3 zero-days and 7 critical vulnerabilities that affect a wide-range of their products and services. The list of patches covers an actively exploited zero-day vulnerability in the Windows Local Security Authority (LSA), as well as vulnerabilities in Kerberos, NFS, and LDAP protocols.
CVE-2022-26931 is a critical Kerberos vulnerability that provides an attacker with privilege elevation if successfully exploited.
CVE-2022-26937 is a critical NFS vulnerability included in the list of fixes. This vulnerability could allow an unauthenticated attacker to execute arbitrary code if successfully exploited over the network. Microsoft recommends disabling NFSV2 and NFSV3 as a means of exploit mitigation using the following PowerShell command. NFSv4.1, is not vulnerable:
powershell PS C:\Set-NfsServerConfiguration -EnableNFSV2 $false -EnableNFSV3 $false
Although most of the LDAP vulnerabilities affect all versions of Windows, CVE-2022-29131 an authenticated attacker can exploit the vulnerability over the network on a domain controller running Windows Server 2019, Windows 10, Windows 11 (x64/arm64), or Windows Server 2022.
CVE-2022-22012 and CVE-2022-29130 are listed as important remote code execution (RCE) vulnerabilities that also affect domain controllers, specifically LDAP. Although, according to the CVSS score for both vulnerabilities, they are deemed critical. An unauthenticated attacker could send a specially crafted request to a vulnerable server that would allow the attacker to remotely execute code within the SYSTEM account context. According to Microsoft, this vulnerability can only be exploited if the
MaxReceiveBuffer LDAP policy is set to a value higher than the default value (10,485,760); otherwise, the system is not vulnerable.
CVE-2022-29139 is also listed as important and it differs from the other LDAP vulnerabilities in that it flips the RCE on its head. If an LDAP client connects to a malicious LDAP server from a Windows host, the malicious server could allow an attacker to remotely execute code within the LDAP client.
_asset.protocol:kerberos and protocol:kerberos and kerberos.errorCode:68 and os:windows
_asset.protocol:nfs and protocol:nfs and os:windows
_asset.protocol:ldap and protocol:ldap and (has:"ldap.isSynchronized" or has:"ldap.domainControllerFunctionality") and type:server and os:windows
Get runZero for free
Find all your Windows NFS, Kerberos, and domain controller assets.Start your trial today
August 4, 2022
Finding DrayTek Vigor routers
The Trellix Threat Labs Vulnerability Research team recently published vulnerability details affecting almost 30 models of DrayTek Vigor routers. This vulnerability resides in the management interface login page and is trivial to exploit via buffer overflow. An …Read More
July 29, 2022
Hunting for X.509 Certificates
X.509 certificates are used to secure communications over both trusted and untrusted networks. Protocols such as Transport Layer Security (TLS) rely on X.509 certificates to keep their communications secure between endpoints. Each X.509 certificate is composed of a public …Read More
June 21, 2022
Finding Microsoft VPN/PPTP with runZero
Last month, researcher Alex Nichols at Nettitude reported a vulnerability in Microsoft’s Windows VPN software that could allow for remote code execution or local privilege escalation by an attacker. This vulnerability lies in a use-after-free condition that can occur in the …Read More