Citrix Netscaler 10.5 HTTP Header Content-type access control

Summaryinfo

A vulnerability classified as critical has been found in Citrix Netscaler 10.5. This impacts an unknown function of the component HTTP Header Handler. This manipulation of the argument Content-type causes access control. This vulnerability is tracked as CVE-2015-2841. Moreover, an exploit is present.

Detailsinfo

A vulnerability classified as critical was found in Citrix Netscaler 10.5 (Network Management Software). Affected by this vulnerability is some unknown processing of the component HTTP Header Handler. The manipulation of the argument Content-type with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. As an impact it is known to affect integrity. The summary by CVE is:

Citrix NetScaler AppFirewall, as used in NetScaler 10.5, allows remote attackers to bypass intended firewall restrictions via a crafted Content-Type header, as demonstrated by the application/octet-stream and text/xml Content-Types.

The weakness was disclosed 03/13/2015 as not defined mailinglist post (Full-Disclosure). The advisory is shared at seclists.org. This vulnerability is known as CVE-2015-2841 since 04/03/2015. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details and also a public exploit are known. MITRE ATT&CK project uses the attack technique T1068 for this issue.

After even before and not, there has been an exploit disclosed. It is possible to download the exploit 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 39 days. During that time the estimated underground price was around $25k-$100k. The code used by the exploit is:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/">
   <soapenv:Header/>
   <soapenv:Body>
      <string>’ union select current_user, 2#</string>
   </soapenv:Body>
</soapenv:Envelope>

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 databases at X-Force (101573), Exploit-DB (36369), OSVDB (119754†) and SecurityTracker (ID 1031928†). Additional details are provided at packetstormsecurity.com. The entry VDB-74633 is pretty similar. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Network Management Software

Vendor

• Citrix

Name

• Netscaler

Version

• 10.5

License

• commercial

Website

• Vendor: https://www.citrix.com/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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