Universal Media Server 7.1.0 Parsing Engine xml external entity reference

Summaryinfo

A vulnerability identified as critical has been detected in Universal Media Server 7.1.0. The affected element is an unknown function of the component Parsing Engine. The manipulation leads to xml external entity reference. This vulnerability is traded as CVE-2018-13416. It is possible to initiate the attack remotely. Furthermore, there is an exploit available.

Detailsinfo

A vulnerability was found in Universal Media Server 7.1.0. It has been rated as critical. This issue affects some unknown functionality of the component Parsing Engine. The manipulation with an unknown input leads to a xml external entity reference vulnerability. Using CWE to declare the problem leads to CWE-611. The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In Universal Media Server (UMS) 7.1.0, the XML parsing engine for SSDP/UPnP functionality is vulnerable to an XML External Entity Processing (XXE) attack. Remote, unauthenticated attackers can use this vulnerability to: (1) Access arbitrary files from the filesystem with the same permission as the user account running UMS, (2) Initiate SMB connections to capture a NetNTLM challenge/response and crack to cleartext password, or (3) Initiate SMB connections to relay a NetNTLM challenge/response and achieve Remote Command Execution in Windows domains.

The bug was discovered 08/01/2018. The weakness was shared 08/03/2018 as not defined mailinglist post (Full-Disclosure). It is possible to read the advisory at seclists.org. The identification of this vulnerability is CVE-2018-13416 since 07/06/2018. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are unknown but a public exploit is available.

The exploit is available at exploit-db.com. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 2 days. During that time the estimated underground price was around $0-$5k.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Exploit-DB (45133). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• Universal Media Server

Version

• 7.1.0

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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