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

  - The pluto IKE daemon in libreswan before 3.15 and Openswan before 2.6.45, when built with NSS, allows     remote attackers to cause a denial of service (assertion failure and daemon restart) via a zero DH g^x     value in a KE payload in a IKE packet. (CVE-2015-3240)

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

The remote Redhat Enterprise Linux 7 host has a package installed that is affected by a vulnerability as referenced in the RHSA-2015:1979 advisory.

    Libreswan is an implementation of IPsec & IKE for Linux. IPsec is the     Internet Protocol Security and uses strong cryptography to provide both     authentication and encryption services. These services allow you to build     secure tunnels through untrusted networks such as virtual private network     (VPN).

    A flaw was discovered in the way Libreswan's IKE daemon processed IKE KE     payloads. A remote attacker could send specially crafted IKE payload with a     KE payload of g^x=0 that, when processed, would lead to a denial of service     (daemon crash). (CVE-2015-3240)

    This issue was discovered by Paul Wouters of Red Hat.

    Note: Please note that when upgrading from an earlier version of Libreswan,     the existing CA certificates in the /etc/ipsec.d/cacerts/ directory and the     existing certificate revocation list (CRL) files from the     /etc/ipsec.d/crls/ directory are automatically imported into the NSS     database. Once completed, these directories are no longer used by     Libreswan. To install new CA certificates or new CRLS, the certutil and     crlutil commands must be used to import these directly into the Network     Security Services (NSS) database.

    This update also adds the following enhancements:

    * This update adds support for RFC 7383 IKEv2 Fragmentation, RFC 7619 Auth     Null and ID Null, INVALID_KE renegotiation, CRL and OCSP support via NSS,     AES_CTR and AES_GCM support for IKEv2, CAVS testing for FIPS compliance.

    In addition, this update enforces FIPS algorithms restrictions in FIPS     mode, and runs Composite Application Validation System (CAVS) testing for     FIPS compliance during package build. A new Cryptographic Algorithm     Validation Program (CAVP) binary can be used to re-run the CAVS tests at     any time. Regardless of FIPS mode, the pluto daemon runs RFC test vectors     for various algorithms.

    Furthermore, compiling on all architectures now enables the -Werror GCC     option, which enhances the security by making all warnings into errors.
    (BZ#1263346)

    * This update also fixes several memory leaks and introduces a sub-second     packet retransmit option. (BZ#1268773)

    * This update improves migration support from Openswan to Libreswan.
    Specifically, all Openswan options that can take a time value without a     suffix are now supported, and several new keywords for use in the     /etc/ipsec.conf file have been introduced. See the relevant man pages for     details. (BZ#1268775)

    * With this update, loopback support via the loopback= option has been     deprecated. (BZ#1270673)

    All Libreswan users are advised to upgrade to these updated packages, which     contain backported patches to correct these issues and add these     enhancements.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

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

The remote Oracle Linux 7 host has a package installed that is affected by a vulnerability as referenced in the ELSA-2015-1979 advisory.

    - Resolves: rhbz#1259208 CVE-2015-3240

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

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

Updated libreswan packages that fix one security issue, several bugs, and add several enhancements are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Moderate security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section.

Libreswan is an implementation of IPsec & IKE for Linux. IPsec is the Internet Protocol Security and uses strong cryptography to provide both authentication and encryption services. These services allow you to build secure tunnels through untrusted networks such as virtual private network (VPN).

A flaw was discovered in the way Libreswan's IKE daemon processed IKE KE payloads. A remote attacker could send specially crafted IKE payload with a KE payload of g^x=0 that, when processed, would lead to a denial of service (daemon crash). (CVE-2015-3240)

This issue was discovered by Paul Wouters of Red Hat.

Note: Please note that when upgrading from an earlier version of Libreswan, the existing CA certificates in the /etc/ipsec.d/cacerts/ directory and the existing certificate revocation list (CRL) files from the /etc/ipsec.d/crls/ directory are automatically imported into the NSS database. Once completed, these directories are no longer used by Libreswan. To install new CA certificates or new CRLS, the certutil and crlutil commands must be used to import these directly into the Network Security Services (NSS) database.

This update also adds the following enhancements :

* This update adds support for RFC 7383 IKEv2 Fragmentation, RFC 7619 Auth Null and ID Null, INVALID_KE renegotiation, CRL and OCSP support via NSS, AES_CTR and AES_GCM support for IKEv2, CAVS testing for FIPS compliance.

In addition, this update enforces FIPS algorithms restrictions in FIPS mode, and runs Composite Application Validation System (CAVS) testing for FIPS compliance during package build. A new Cryptographic Algorithm Validation Program (CAVP) binary can be used to re-run the CAVS tests at any time. Regardless of FIPS mode, the pluto daemon runs RFC test vectors for various algorithms.

Furthermore, compiling on all architectures now enables the '-Werror' GCC option, which enhances the security by making all warnings into errors. (BZ#1263346)

* This update also fixes several memory leaks and introduces a sub-second packet retransmit option. (BZ#1268773)

* This update improves migration support from Openswan to Libreswan.
Specifically, all Openswan options that can take a time value without a suffix are now supported, and several new keywords for use in the /etc/ipsec.conf file have been introduced. See the relevant man pages for details. (BZ#1268775)

* With this update, loopback support via the 'loopback=' option has been deprecated. (BZ#1270673)

All Libreswan users are advised to upgrade to these updated packages, which contain backported patches to correct these issues and add these enhancements.

A flaw was discovered in the way Libreswan's IKE daemon processed IKE KE payloads. A remote attacker could send specially crafted IKE payload with a KE payload of g^x=0 that, when processed, would lead to a denial of service (daemon crash). (CVE-2015-3240)

Note: Please note that when upgrading from an earlier version of Libreswan, the existing CA certificates in the /etc/ipsec.d/cacerts/ directory and the existing certificate revocation list (CRL) files from the /etc/ipsec.d/crls/ directory are automatically imported into the NSS database. Once completed, these directories are no longer used by Libreswan. To install new CA certificates or new CRLS, the certutil and crlutil commands must be used to import these directly into the Network Security Services (NSS) database.

This update also adds the following enhancements :

  - This update adds support for RFC 7383 IKEv2     Fragmentation, RFC 7619 Auth Null and ID Null,     INVALID_KE renegotiation, CRL and OCSP support via NSS,     AES_CTR and AES_GCM support for IKEv2, CAVS testing for     FIPS compliance.

In addition, this update enforces FIPS algorithms restrictions in FIPS mode, and runs Composite Application Validation System (CAVS) testing for FIPS compliance during package build. A new Cryptographic Algorithm Validation Program (CAVP) binary can be used to re-run the CAVS tests at any time. Regardless of FIPS mode, the pluto daemon runs RFC test vectors for various algorithms.

Furthermore, compiling on all architectures now enables the '-Werror' GCC option, which enhances the security by making all warnings into errors.

  - This update also fixes several memory leaks and     introduces a sub-second packet retransmit option.

  - This update improves migration support from Openswan to     Libreswan. Specifically, all Openswan options that can     take a time value without a suffix are now supported,     and several new keywords for use in the /etc/ipsec.conf     file have been introduced. See the relevant man pages     for details.

  - With this update, loopback support via the 'loopback='     option has been deprecated.

The remote host is affected by the vulnerability described in GLSA-201603-13 (Libreswan: Multiple Vulnerabilities)

    The pluto IKE daemon in Libreswan, when built with NSS, allows remote       attackers to cause a Denial of Service (assertion failure and daemon       restart) via a zero DH g^x value in a KE payload in a IKE packet.
      Additionally, remote attackers could cause a Denial of Service (daemon       restart) via an IKEv1 packet with (1) unassigned bits set in the IPSEC       DOI value or (2) the next payload value set to ISAKMP_NEXT_SAK.
  Impact :

    Remote attackers could possibly cause Denial of Service.
  Workaround :

    There is no known workaround at this time.

ID	Name	Product	Family	Published	Updated	Severity
218918	Linux Distros Unpatched Vulnerability : CVE-2015-3240	Nessus	Misc.	3/4/2025	3/4/2025	high
86744	RHEL 7 : libreswan (RHSA-2015:1979)	Nessus	Red Hat Local Security Checks	11/5/2015	4/15/2025	high
86715	Oracle Linux 7 : libreswan (ELSA-2015-1979)	Nessus	Oracle Linux Local Security Checks	11/4/2015	4/29/2025	high
86711	CentOS 7 : libreswan (CESA-2015:1979)	Nessus	CentOS Local Security Checks	11/4/2015	1/4/2021	medium
86749	Scientific Linux Security Update : libreswan on SL7.x x86_64 (20151104)	Nessus	Scientific Linux Local Security Checks	11/5/2015	1/14/2021	medium
89906	GLSA-201603-13 : Libreswan: Multiple Vulnerabilities	Nessus	Gentoo Local Security Checks	3/14/2016	1/11/2021	medium

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