Double free vulnerability in MIT Kerberos 5 (aka krb5) allows attackers to have unspecified impact via vectors involving automatic deletion of security contexts on error.

The remote NewStart CGSL host, running version MAIN 6.06, has krb5 packages installed that are affected by multiple vulnerabilities:

  - plugins/preauth/pkinit/pkinit_crypto_openssl.c in MIT Kerberos 5 (aka krb5) through 1.15.2 mishandles     Distinguished Name (DN) fields, which allows remote attackers to execute arbitrary code or cause a denial     of service (buffer overflow and application crash) in situations involving untrusted X.509 data, related     to the get_matching_data and X509_NAME_oneline_ex functions. NOTE: this has security relevance only in use     cases outside of the MIT Kerberos distribution, e.g., the use of get_matching_data in KDC certauth plugin     code that is specific to Red Hat. (CVE-2017-15088)

  - The process_chpw_request function in schpw.c in the password-changing functionality in kadmind in MIT     Kerberos 5 (aka krb5) 1.7 through 1.9 frees an invalid pointer, which allows remote attackers to execute     arbitrary code or cause a denial of service (daemon crash) via a crafted request that triggers an error     condition. (CVE-2011-0285)

  - schpw.c in the kpasswd service in kadmind in MIT Kerberos 5 (aka krb5) before 1.11.3 does not properly     validate UDP packets before sending responses, which allows remote attackers to cause a denial of service     (CPU and bandwidth consumption) via a forged packet that triggers a communication loop, as demonstrated by     krb_pingpong.nasl, a related issue to CVE-1999-0103. (CVE-2002-2443)

  - 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. (CVE-2006-3084)

  - The RPC library in Kerberos 5 1.4 through 1.4.4, and 1.5 through 1.5.1, as used in Kerberos administration     daemon (kadmind) and other products that use this library, calls an uninitialized function pointer in     freed memory, which allows remote attackers to cause a denial of service (crash) and possibly execute     arbitrary code via unspecified vectors. (CVE-2006-6143)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Double free vulnerability in MIT Kerberos 5 (aka krb5) allows attackers to have unspecified impact via     vectors involving automatic deletion of security contexts on error. (CVE-2017-11462)

Note that Nessus relies on the presence of the package as reported by the vendor.

An update of the krb5 package has been released.

According to the versions of the krb5 packages installed, the EulerOS Virtualization installation on the remote host is affected by the following vulnerabilities :

  - Double free vulnerability in MIT Kerberos 5 (aka krb5)     allows attackers to have unspecified impact via vectors     involving automatic deletion of security contexts on     error.(CVE-2017-11462)

  - A Reachable Assertion issue was discovered in the KDC     in MIT Kerberos 5 (aka krb5) before 1.17. If an     attacker can obtain a krbtgt ticket using an older     encryption type (single-DES, triple-DES, or RC4), the     attacker can crash the KDC by making an S4U2Self     request.(CVE-2018-20217)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the versions of the krb5 packages installed, the EulerOS Virtualization for ARM 64 installation on the remote host is affected by the following vulnerabilities :

  - Double free vulnerability in MIT Kerberos 5 (aka krb5)     allows attackers to have unspecified impact via vectors     involving automatic deletion of security contexts on     error.(CVE-2017-11462)

  - A Reachable Assertion issue was discovered in the KDC     in MIT Kerberos 5 (aka krb5) before 1.17. If an     attacker can obtain a krbtgt ticket using an older     encryption type (single-DES, triple-DES, or RC4), the     attacker can crash the KDC by making an S4U2Self     request.(CVE-2018-20217)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

According to the version of the krb5 packages installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  - Double free vulnerability in MIT Kerberos 5 (aka krb5)     allows attackers to have unspecified impact via vectors     involving automatic deletion of security contexts on     error.(CVE-2017-11462)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for krb5 fixes several issues. This security issue was fixed :

  - CVE-2017-11462: Prevent automatic security context     deletion to prevent double-free (bsc#1056995).

  - CVE-2018-5729: NULL pointer dereference in kadmind or DN     container check bypass by supplying special crafted data     (bsc#1083926).

  - CVE-2018-5730: DN container check bypass by supplying     special crafted data (bsc#1083927).

The update package also includes non-security fixes. See advisory for details.

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

- Prevent applications from accidentally implementing     CVE-2017-11462 (double free if sec_context is copied).

  - fc26+: Add ccselect hostrealm module for ccache     selection based on service hostname.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website.
Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

MIT reports :

CVE-2017-11368 :

In MIT krb5 1.7 and later, an authenticated attacker can cause an assertion failure in krb5kdc by sending an invalid S4U2Self or S4U2Proxy request.

CVE-2017-11462 :

RFC 2744 permits a GSS-API implementation to delete an existing security context on a second or subsequent call to gss_init_sec_context() or gss_accept_sec_context() if the call results in an error. This API behavior has been found to be dangerous, leading to the possibility of memory errors in some callers. For safety, GSS-API implementations should instead preserve existing security contexts on error until the caller deletes them.

All versions of MIT krb5 prior to this change may delete acceptor contexts on error. Versions 1.13.4 through 1.13.7, 1.14.1 through 1.14.5, and 1.15 through 1.15.1 may also delete initiator contexts on error.

This update for krb5 fixes several issues.

This security issue was fixed :

  - CVE-2017-11462: Prevent automatic security context     deletion to prevent double-free (bsc#1056995)

These non-security issues were fixed :

  - Set 'rdns' and 'dns_canonicalize_hostname' to false in     krb5.conf in order to improve client security in     handling service principle names. (bsc#1054028)

  - Prevent kadmind.service startup failure caused by     absence of LDAP service. (bsc#903543)

  - Remove main package's dependency on systemd     (bsc#1032680)

This update was imported from the SUSE:SLE-12-SP2:Update update project.

This update for krb5 fixes several issues. This security issue was fixed :

  - CVE-2017-11462: Prevent automatic security context     deletion to prevent double-free (bsc#1056995)

The update package also includes non-security fixes. See advisory for details.

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
266225	NewStart CGSL MAIN 6.06 : krb5 Multiple Vulnerabilities (NS-SA-2025-0215)	Nessus	NewStart CGSL Local Security Checks	critical
220178	Linux Distros Unpatched Vulnerability : CVE-2017-11462	Nessus	Misc.	critical
202838	Photon OS 1.0: Krb5 PHSA-2017-0038	Nessus	PhotonOS Local Security Checks	critical
135629	EulerOS Virtualization 3.0.2.2 : krb5 (EulerOS-SA-2020-1467)	Nessus	Huawei Local Security Checks	critical
134481	EulerOS Virtualization for ARM 64 3.0.2.0 : krb5 (EulerOS-SA-2020-1192)	Nessus	Huawei Local Security Checks	critical
130871	EulerOS 2.0 SP5 : krb5 (EulerOS-SA-2019-2162)	Nessus	Huawei Local Security Checks	critical
129251	EulerOS 2.0 SP3 : krb5 (EulerOS-SA-2019-2058)	Nessus	Huawei Local Security Checks	critical
128900	EulerOS 2.0 SP2 : krb5 (EulerOS-SA-2019-1848)	Nessus	Huawei Local Security Checks	critical
108826	SUSE SLES11 Security Update : krb5 (SUSE-SU-2018:0859-1)	Nessus	SuSE Local Security Checks	critical
105909	Fedora 27 : krb5 (2017-7a22a80c7e)	Nessus	Fedora Local Security Checks	critical
103953	FreeBSD : krb5 -- Multiple vulnerabilities (3f3837cc-48fb-4414-aa46-5b1c23c9feae)	Nessus	FreeBSD Local Security Checks	critical
103799	openSUSE Security Update : krb5 (openSUSE-2017-1145)	Nessus	SuSE Local Security Checks	critical
103742	SUSE SLED12 / SLES12 Security Update : krb5 (SUSE-SU-2017:2659-1)	Nessus	SuSE Local Security Checks	critical
103544	Fedora 25 : krb5 (2017-56e23bc2b5)	Nessus	Fedora Local Security Checks	critical
103098	Fedora 26 : krb5 (2017-10c74147f9)	Nessus	Fedora Local Security Checks	critical

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CVE-2017-11462

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