#VU32374 Permissions, Privileges, and Access Controls in Kerberos 5 - CVE-2015-2694

Vulnerability identifier: #VU32374

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2015-2694

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Kerberos 5
Client/Desktop applications / Software for system administration

Vendor: MIT

Description

The vulnerability allows a remote non-authenticated attacker to read and manipulate data.

The kdcpreauth modules in MIT Kerberos 5 (aka krb5) 1.12.x and 1.13.x before 1.13.2 do not properly track whether a client's request has been validated, which allows remote attackers to bypass an intended preauthentication requirement by providing (1) zero bytes of data or (2) an arbitrary realm name, related to plugins/preauth/otp/main.c and plugins/preauth/pkinit/pkinit_srv.c.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Kerberos 5: 1.0 - 1.18.2

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External links
https://krbdev.mit.edu/rt/Ticket/Display.html?id=8160
https://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
https://www.securityfocus.com/bid/74824
https://www.ubuntu.com/usn/USN-2810-1
https://github.com/krb5/krb5/commit/e3b5a5e5267818c97750b266df50b6a3d4649604

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.