A vulnerability has been found in Heimdal PRO v2.2.190, but it is most likely also present in Heimdal FREE and Heimdal CORP. Faulty permissions on the directory "C:\ProgramData\Heimdal Security\Heimdal Agent" allow BUILTIN\Users to write new files to the directory. On startup, the process Heimdal.MonitorServices.exe running as SYSTEM will attempt to load version.dll from this directory. Placing a malicious version.dll in this directory will result in privilege escalation. NOTE: any affected Heimdal products are completely unrelated to the Heimdal vendor of a Kerberos 5 product on the h5l.org web site.

An issue was discovered in Heimdal PRO 2.2.190. As part of the scanning feature, a process called md.hs writes an executable called CS1.tmp to C:\windows\TEMP. Afterwards the executable is run. It is possible for an attacker to create the file first, let md.hs overwrite it, and then rewrite the file in the window between md.hs closing the file and executing it. This can be exploited via opportunistic locks and a high priority thread. The vulnerability is triggered when a scan starts. NOTE: any affected Heimdal products are completely unrelated to the Heimdal vendor of a Kerberos 5 product on the h5l.org web site.

In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the _kdc_as_rep function in kdc/kerberos5.c and the der_length_visible_string function in lib/asn1/der_length.c.

The transit path validation code in Heimdal before 7.3 might allow attackers to bypass the capath policy protection mechanism by leveraging failure to add the previous hop realm to the transit path of issued tickets.

Heimdal before 7.4 allows remote attackers to impersonate services with Orpheus' Lyre attacks because it obtains service-principal names in a way that violates the Kerberos 5 protocol specification. In _krb5_extract_ticket() the KDC-REP service name must be obtained from the encrypted version stored in 'enc_part' instead of the unencrypted version stored in 'ticket'. Use of the unencrypted version provides an opportunity for successful server impersonation and other attacks. NOTE: this CVE is only for Heimdal and other products that embed Heimdal code; it does not apply to other instances in which this part of the Kerberos 5 protocol specification is violated.

Buffer overflow in libtelnet/encrypt.c in telnetd in FreeBSD 7.3 through 9.0, MIT Kerberos Version 5 Applications (aka krb5-appl) 1.0.2 and earlier, Heimdal 1.5.1 and earlier, GNU inetutils, and possibly other products allows remote attackers to execute arbitrary code via a long encryption key, as exploited in the wild in December 2011.

The gss_userok function in appl/ftp/ftpd/gss_userok.c in Heimdal 0.7.2 does not allocate memory for the ticketfile pointer before calling free, which allows remote attackers to have an unknown impact via an invalid username. NOTE: the vulnerability was originally reported for ftpd.c, but this is incorrect.

The (1) ftpd and (2) ksu programs in (a) MIT Kerberos 5 (krb5) up to 1.5, and 1.4.x before 1.4.4, and (b) Heimdal 0.7.2 and earlier, do not check return codes for setuid calls, which might allow local users to gain privileges by causing setuid to fail to drop privileges. NOTE: as of 20060808, it is not known whether an exploitable attack scenario exists for these issues.

The (1) krshd and (2) v4rcp applications in (a) MIT Kerberos 5 (krb5) up to 1.5, and 1.4.x before 1.4.4, when running on Linux and AIX, and (b) Heimdal 0.7.2 and earlier, do not check return codes for setuid calls, which allows local users to gain privileges by causing setuid to fail to drop privileges using attacks such as resource exhaustion.

telnetd in Heimdal 0.6.x before 0.6.6 and 0.7.x before 0.7.2 allows remote unauthenticated attackers to cause a denial of service (server crash) via unknown vectors that trigger a null dereference.