Security alert - critical vulnerabilities

Critical Vulnerabilities of December 2020

12/11/20 9:36 AM  |  by RedLegg Blog

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VMware Workspace One Access, Access Connector, Identity Manager, and Identity Manager Connector address have a command injection vulnerability.

Identifier: CVE-2020-4006

Exploit or POC: YES (Actively being exploited*)


A malicious actor with network access to the administrative configurator on port 8443 and a valid password for the configurator admin account can execute commands with unrestricted privileges on the underlying operating system. This account is internal to the impacted products and a password is set at the time of deployment. A malicious actor must possess this password to attempt to exploit CVE-2020-4006. Examples of how this password could be obtained by a malicious actor are documented in T1586 of the MITRE ATT&CK database.

Mitigation recommendation: VMware has released a workaround and a patch. The patch from VMware is recommended. Threat actors are actively exploiting this vulnerability


Null Pointer Dereference Flaw in OpenSSL

Identifier: CVE-2020-1971

Exploit or POC: No evidence of exploitation yet.


The X.509 GeneralName type is a generic type for representing different types of names. One of those name types is known as EDIPartyName. OpenSSL provides a function GENERAL_NAME_cmp which compares different instances of a GENERAL_NAME to see if they are equal or not. This function behaves incorrectly when both GENERAL_NAMEs contain an EDIPARTYNAME. A NULL pointer dereference and a crash may occur leading to a possible denial of service attack.

OpenSSL itself uses the GENERAL_NAME_cmp function for two purposes: 1) Comparing CRL distribution point names between an available CRL and a CRL distribution point embedded in an X509 certificate 2) When verifying that a timestamp response token signer matches the timestamp authority name (exposed via the API functions TS_RESP_verify_response and TS_RESP_verify_token) If an attacker can control both items being compared then that attacker could trigger a crash. For example if the attacker can trick a client or server into checking a malicious certificate against a malicious CRL then this may occur.

Note that some applications automatically download CRLs based on a URL embedded in a certificate. This checking happens prior to the signatures on the certificate and CRL being verified. OpenSSL's s_server, s_client and verify tools have support for the "-crl_download" option which implements automatic CRL downloading and this attack has been demonstrated to work against those tools. Note that an unrelated bug means that affected versions of OpenSSL cannot parse or construct correct encodings of EDIPARTYNAME. However it is possible to construct a malformed EDIPARTYNAME that OpenSSL's parser will accept and hence trigger this attack. All OpenSSL 1.1.1 and 1.0.2 versions are affected by this issue. Other OpenSSL releases are out of support and have not been checked. Fixed in OpenSSL 1.1.1i (Affected 1.1.1-1.1.1h). Fixed in OpenSSL 1.0.2x (Affected 1.0.2-1.0.2w).

Mitigation recommendation: The only mitigation is to update openssl.


Apache Struts2 Code Execution Vulnerability

Identifier: CVE-2020-17530

Exploit or POC: No evidence of exploitation yet.


Description: On December 8, 2020, Apache Struts2 issued a risk notice for Apache Struts2 code execution vulnerability. The vulnerability number is CVE-2020-17530. The vulnerability level is high risk. In a specific environment, remote attackers can cause arbitrary code execution by constructing malicious OGNL expressions.

Mitigation recommendation: Avoid using forced OGNL evaluation on untrusted user input, and/or upgrade to Struts 2.5.26 which checks if expression evaluation won't lead to the double evaluation.


Multiple Vulnrabilities in Windows Server 2019 (Server Core Installation)

Identifier: CVE-2020-17094, CVE-2020-17098, CVE-2020-16996, CVE-2020-17099, CVE-2020-17103, CVE-2020-17096, CVE-2020-16958, CVE-2020-16959, CVE-2020-16960, CVE-2020-16961, CVE-2020-16962, CVE-2020-16963, CVE-2020-16964, CVE-2020-17092, CVE-2020-17134, CVE-2020-17136, CVE-2020-17139, CVE-2020-17140, CVE-2020-17095

Exploit or POC: No


CVE-2020-17094    Windows Error Reporting Information Disclosure Vulnerability

CVE-2020-17098    Windows GDI+ Information Disclosure Vulnerability

CVE-2020-16996    Kerberos Security Feature Bypass Vulnerability

CVE-2020-17099    Windows Lock Screen Security Feature Bypass Vulnerability

CVE-2020-17103     Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability

CVE-2020-17096    Windows NTFS Remote Code Execution Vulnerability

CVE-2020-16958    Windows Backup Engine Elevation of Privilege Vulnerability

CVE-2020-16959    Windows Backup Engine Elevation of Privilege Vulnerability

CVE-2020-16960    Windows Backup Engine Elevation of Privilege Vulnerability

CVE-2020-16961     Windows Backup Engine Elevation of Privilege Vulnerability

CVE-2020-16962    Windows Backup Engine Elevation of Privilege Vulnerability

CVE-2020-16963     Windows Backup Engine Elevation of Privilege Vulnerability

CVE-2020-16964    Windows Backup Engine Elevation of Privilege Vulnerability

CVE-2020-17092    Windows Network Connections Service Elevation of Privilege Vulnerability

CVE-2020-17134     Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability

CVE-2020-17136     Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability

CVE-2020-17139     Windows Overlay Filter Security Feature Bypass Vulnerability

CVE-2020-17140     Windows SMB Information Disclosure Vulnerability

CVE-2020-17095    Hyper-V Remote Code Execution Vulnerability

Mitigation recommendation: Currently the only mitigation method is to patch your windows servers.


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*Active exploits may have changed since the dissemination of this bulletin which was December 9. This list does not represent the full list of current vulnerabilties.

**And to see the full list of vulnerabilities we released with this batch.

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