A vulnerability has been found in PuTTY 0.48/0.49/0.53 (Connectivity Software) and classified as very critical. This vulnerability affects an unknown part of the component NULL Character Handler. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Multiple SSH2 servers and clients do not properly handle strings with null characters in them when the string length is specified by a length field, which could allow remote attackers to cause a denial of service or possibly execute arbitrary code due to interactions with the use of null-terminated strings as implemented using languages such as C, as demonstrated by the SSHredder SSH protocol test suite.

The weakness was released 12/23/2002 as confirmed advisory (CERT.org). The advisory is available at cert.org. This vulnerability was named CVE-2002-1360. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/09/2018).

The vulnerability scanner Nessus provides a plugin with the ID 48968 (SSH Malformed Packet Vulnerabilities - Cisco Systems), which helps to determine the existence of the flaw in a target environment. It is assigned to the family CISCO and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 38223 (Multiple Vendor SSH2 Implementation Vulnerabilities).

Applying a patch is able to eliminate this problem. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (48968). Entries connected to this vulnerability are available at 19243, 19244 and 19245.

Productinfo

Type

• Connectivity Software

Name

• PuTTY

Version

• 0.48
• 0.49
• 0.53

License

• open-source

CPE 2.3info

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CPE 2.2info

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