GSS-NTLMSSP up to 1.1.x NTLM Authentication ntlm_str_convert outlen out-of-bounds write

Summaryinfo

A vulnerability, which was classified as critical, has been found in GSS-NTLMSSP up to 1.1.x. This affects the function ntlm_str_convert of the component NTLM Authentication. This manipulation of the argument outlen causes out-of-bounds write. This vulnerability is tracked as CVE-2023-25564. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in GSS-NTLMSSP up to 1.1.x. It has been declared as critical. Affected by this vulnerability is the function ntlm_str_convert of the component NTLM Authentication. The manipulation of the argument outlen with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

GSS-NTLMSSP is a mechglue plugin for the GSSAPI library that implements NTLM authentication. Prior to version 1.2.0, memory corruption can be triggered when decoding UTF16 strings. The variable `outlen` was not initialized and could cause writing a zero to an arbitrary place in memory if `ntlm_str_convert()` were to fail, which would leave `outlen` uninitialized. This can lead to a denial of service if the write hits unmapped memory or randomly corrupts a byte in the application memory space. This vulnerability can trigger an out-of-bounds write, leading to memory corruption. This vulnerability can be triggered via the main `gss_accept_sec_context` entry point. This issue is fixed in version 1.2.0.

The weakness was disclosed 02/14/2023 as GHSA-r85x-q5px-9xfq. It is possible to read the advisory at github.com. This vulnerability is known as CVE-2023-25564 since 02/07/2023. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 240491 (Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS : GSS NTLMSSP vulnerabilities (USN-7588-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.2.0 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch c753000eb31835c0664e528fbc99378ae0cbe950 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (240491) and CERT Bund (WID-SEC-2023-1238). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Oracle Linux
• Red Hat Enterprise Linux
• RESF Rocky Linux

Productinfo

Name

• GSS-NTLMSSP

Version

• 1.0
• 1.1

License

• open-source

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