Stack-based buffer overflow in SMBLogonServer of the rlmsmb experimental module for FreeRADIUS 0.9.3 and earlier allows remote attackers to execute arbitrary code via a long User-Password attribute.

A vulnerability was found in FreeRadius. An attacker can reflect the received scalar and element from the server in it's own commit message, and subsequently reflect the confirm value as well. This causes the adversary to successfully authenticate as the victim. Fortunately, the adversary will not posses the negotiated session key, meaning the adversary cannot actually perform any actions as this user.

A vulnerability was found in FreeRadius. An invalid curve attack allows an attacker to authenticate as any user (without knowing the password). The problem is that on the reception of an EAP-PWD Commit frame, FreeRADIUS doesn't verify whether the received elliptic curve point is valid.

The TLS session cache in FreeRADIUS 2.1.1 through 2.1.7, 3.0.x before 3.0.14, 3.1.x before 2017-02-04, and 4.0.x before 2017-02-04 fails to reliably prevent resumption of an unauthenticated session, which allows remote attackers (such as malicious 802.1X supplicants) to bypass authentication via PEAP or TTLS.

Multiple buffer overflows in FreeRADIUS 1.0.3 and 1.0.4 allow remote attackers to cause denial of service (crash) via (1) the rlmsqlcounter module or (2) unknown vectors "while expanding %t".

Buffer overflow in digest calculation function of multiple RADIUS implementations allows remote attackers to cause a denial of service and possibly execute arbitrary code via shared secret data.

Buffer overflow in the sqlescapefunc function in the SQL module for FreeRADIUS 1.0.2 and earlier allows remote attackers to cause a denial of service (crash).

SQL injection vulnerability in the radiusxlat function in the SQL module for FreeRADIUS 1.0.2 and earlier allows remote authenticated users to execute arbitrary SQL commands via (1) groupmembershipquery, (2) simulcountquery, or (3) simulverifyquery configuration entries.

SQL injection vulnerability in the rlmsqlcounter module in FreeRADIUS 1.0.3 and 1.0.4 allows remote attackers to execute arbitrary SQL commands via unknown attack vectors.

Unspecified vulnerability in FreeRADIUS 1.0.0 up to 1.1.0 allows remote attackers to bypass authentication or cause a denial of service (server crash) via "Insufficient input validation" in the EAP-MSCHAPv2 state machine module.

FreeRADIUS 2.2.x before 2.2.8 and 3.0.x before 3.0.9 does not properly check revocation of intermediate CA certificates.

freeradius-dialupadmin in freeradius 2.0.4 allows local users to overwrite arbitrary files via a symlink attack on temporary files in (1) backupradacct, (2) cleanradacct, (3) monthlytotstats, (4) totstats, and (5) truncateradacct.

DISPUTED Buffer overflow in the SMBConnectServer function in FreeRadius 1.1.3 and earlier allows attackers to execute arbitrary code related to the server desthost field of an SMBHandleType instance. NOTE: the impact of this issue has been disputed by a reliable third party and the vendor, who states that exploitation is limited "only to local administrators who have write access to the server configuration files." CVE concurs with the dispute.

Off-by-one error in the sqlerror function in sqlunixodbc.c in FreeRADIUS 1.0.2.5-5, and possibly other versions including 1.0.4, might allow remote attackers to cause a denial of service (crash) and possibly execute arbitrary code by causing the external database query to fail. NOTE: this single issue is part of a larger-scale disclosure, originally by SUSE, which reported multiple issues that were disputed by FreeRADIUS. Disputed issues included file descriptor leaks, memory disclosure, LDAP injection, and other issues. Without additional information, the most recent FreeRADIUS report is being regarded as the authoritative source for this CVE identifier.

DFN-CERT reported [1] a vulnerability in the OCSP feature in FreeRADIUS 2.1.11 where it does not verify the status of a certificate (e.g. if the certificate was revoked).

No further details, or a patch, were provided. According to the changelog on the FreeRADIUS site [2], OCSP support was added in version 2.1.11:

OCSP support from Alex Bergmann. See raddb/eap.conf, "ocsp" section.

Therefore earlier versions of FreeRADIUS are not affected by this flaw.

[1] http://seclists.org/oss-sec/2011/q3/105 [2] http://freeradius.org/

Statement:

Not vulnerable. This issue did not affect the versions of freeradius as shipped with Red Hat Enterprise Linux 4, 5, or 6.

A fundamental design flaw within the RADIUS protocol has been proven to be exploitable, compromising the integrity in the RADIUS Access-Request process. The attack allows a malicious user to modify packets in a way that would be indistinguishable to a RADIUS client or server. To be successful, the attacker must have the ability to inject themselves between the client and server.

Multiple RADIUS implementations do not properly validate the Vendor-Length of the Vendor-Specific attribute, which allows remote attackers to cause a denial of service (crash) via a Vendor-Length that is less than 2.

raddecode in FreeRADIUS 0.9.2 and earlier allows remote attackers to cause a denial of service (crash) via a short RADIUS string attribute with a tag, which causes memcpy to be called with a -1 length argument, as demonstrated using the Tunnel-Password attribute.

Memory leak in FreeRADIUS before 1.0.1 allows remote attackers to cause a denial of service (memory exhaustion) via a series of Access-Request packets with (1) Ascend-Send-Secret, (2) Ascend-Recv-Secret, or (3) Tunnel-Password attributes.

FreeRADIUS before 1.0.1 allows remote attackers to cause a denial of service (core dump) via malformed USR vendor-specific attributes (VSA) that cause a memcpy operation with a -1 argument.

FreeRADIUS before 1.0.1 allows remote attackers to cause a denial of service (server crash) by sending an Ascend-Send-Secret attribute without the required leading packet.

FreeRADIUS RADIUS server allows remote attackers to cause a denial of service (CPU consumption) via a flood of Access-Request packets.

Memory leak in freeRADIUS 1.1.5 and earlier allows remote attackers to cause a denial of service (memory consumption) via a large number of EAP-TTLS tunnel connections using malformed Diameter format attributes, which causes the authentication request to be rejected but does not reclaim VALUEPAIR data structures.

It was reported [1],[2] that an error when processing DHCP requests with the 'Relay Agent Information' option (82) in src/lib/dhcp.c could be exploited to cause an infinite loop, in the process denying further requests via a packet with multiple sub-options.

According to the upstream report, this flaw seems to only affect 2.1.9 and was fixed [3] in 2.1.10.

[1] https://bugs.freeradius.org/bugzilla/showbug.cgi?id=77 [2] http://secunia.com/advisories/41621 [3] http://github.com/alandekok/freeradius-server/commit/4dc7800b866f889a1247685bbaa6dd4238a56279

The offending file (dhcp.c) is not present in the version of freeradius as provided with Red Hat Enterprise Linux 5 (1.1.3).

It was reported [1],[2] that an error when processing requests queued for more than 30 seconds in src/main/event.c could be exploited to cause the process to crash by sending a large number of requests for an extended period of time.

This flaw seems to only affect 2.1.x and was fixed [3] in 2.1.10.

[1] https://bugs.freeradius.org/bugzilla/showbug.cgi?id=35 [2] http://secunia.com/advisories/41621 [3] http://github.com/alandekok/freeradius-server/commit/ff94dd35673bba1476594299d31ce8293b8bd223

The offending file (event.c), nor the affected function (waitforchildtodie()) are not present in the version of freeradius as provided with Red Hat Enterprise Linux 5 (1.1.3).

It was reported [1],[2] that an error when processing requests queued for more than 30 seconds in src/main/event.c could be exploited to cause the process to crash by sending a large number of requests for an extended period of time.

This flaw seems to only affect 2.1.x and was fixed [3] in 2.1.10.

[1] https://bugs.freeradius.org/bugzilla/showbug.cgi?id=35 [2] http://secunia.com/advisories/41621 [3] http://github.com/alandekok/freeradius-server/commit/ff94dd35673bba1476594299d31ce8293b8bd223

The offending file (event.c), nor the affected function (waitforchildtodie()) are not present in the version of freeradius as provided with Red Hat Enterprise Linux 5 (1.1.3).

It was reported [1],[2] that an error when processing DHCP requests with the 'Relay Agent Information' option (82) in src/lib/dhcp.c could be exploited to cause an infinite loop, in the process denying further requests via a packet with multiple sub-options.

According to the upstream report, this flaw seems to only affect 2.1.9 and was fixed [3] in 2.1.10.

[1] https://bugs.freeradius.org/bugzilla/showbug.cgi?id=77 [2] http://secunia.com/advisories/41621 [3] http://github.com/alandekok/freeradius-server/commit/4dc7800b866f889a1247685bbaa6dd4238a56279

The offending file (dhcp.c) is not present in the version of freeradius as provided with Red Hat Enterprise Linux 5 (1.1.3).

https://kb.cert.org/vuls/id/456537 discloses the new Blast-RADIUS attack: Overview -------- A vulnerability in the RADIUS protocol allows an attacker allows an attacker to forge an authentication response in cases where a Message-Authenticator attribute is not required or enforced. This vulnerability results from a cryptographically insecure integrity check when validating authentication responses from a RADIUS server.

Description ----------- RADIUS is a popular lightweight authentication protocol used for networking devices specified in IETF 2058 as early as 1997 (obsoleted by RFC 2138 and then RFC 2865. There have been several other IETF standards (RADIUS/TCP, RADIUS/TLS and RADIUS/DTLS) that cover and enhance various parts of the specification for the use of RADIUS in authentication. RADIUS is widely used to authenticate both users and devices and widely supported by networking devices, from basic network switches to more complex VPN solutions. Recently, RADIUS has also been adopted in much of the cloud services that provide tiered, role-based access-control to resources. As a client-server protocol, RADIUS uses a Request-Response model to verify authentication requests and further provide any role-based access using Groups. RADIUS can also be proxied to support multi-tenant roaming access services.

A vulnerability in the verification of RADIUS Response from a RADIUS server has been disclosed by a team of researchers from UC San Diego and their partners. An attacker, with access to the network where the RADIUS protocol is being transmitted, can spoof a UDP-based RADIUS Response packet to modify any valid Response (Access-Accept, Access-Reject, or Access-Challenge) to any other response, with almost any content, completely under the attackers control. This allows the attacker to transform a Reject into an Accept without knowledge of the shared secret between the RADIUS client and server. The attack is possible due to a basic flaw in the RADIUS protocol specification that uses a MD5 hash to verify the response, along with the fact that part of the hashed text is predictable allowing for a chosen-prefix collision. The attack, demonstrated by UCSD team, takes advantage of the chosen-prefix collision of the MD5 message in a novel way. The widespread use of RADIUS and its adoption into the cloud allows for such attacks to pose a reasonable threat to the authentication verification process that relies on RADIUS.

RADIUS servers that only perform Extensible Authentication Protocol (EAP), as specified in RFC 3579, are unaffected by this attack. The EAP authentication messages require the Message-Authenticator attribute, which will prevent these attacks from succeeding. The use of TLS (or DTLS) encryption can also prevent such attacks from succeeding. However, RADIUS over TCP itself can still be susceptible to this attack, with more advanced man-in-the-middle scenarios, to successfully attack the TCP connection.

Finally as explained by Alan Dekok, developer of FreeRadius open source software -

The key to the attack is that in many cases, Access-Request packets have no authentication or integrity checks. An attacker can then perform a chosen prefix attack, which allows modifying the Access-Request in order to replace a valid response with one chosen by the attacker. Even though the response is authenticated and integrity checked, the chosen prefix vulnerability allows the attacker to modify the response packet, almost at will.

Impact ------ An attacker with access to the network where RADIUS Access-Request is transported can craft a response to the RADIUS server irrespective of the type of response (Access-Accept, Access-Reject, Access-Challenge, or Protocol-Error) to modify the response to any of the valid responses. This can allow an attacker to change the Reject response to an Accept or vice versa. The attack can also potentially intercept an Access-Challenge, typically used in Multi-Factor Authentication (MFA), and modify it to an Access-Accept, thus bypassing the MFA used within RADIUS. Due to the flexible, proxied nature of the RADIUS protocol, any server in the chain of proxied RADIUS servers can be targeted to succeed in the attack.

Solution -------- RADIUS-compliant software and hardware manufacturers should adopt the recommendations from the https://networkradius.com/assets/pdf/radiusandmd5collisions.pdf document to mitigate the risk of the RADIUS protocol limitations identified in this attack. Manufacturers who bundle the open-source RADIUS implementations, such as FreeRadius, should update to the latest available software for both clients and servers and, at a minimum, require the use of the Message-Authenticator for RADIUS Network operators who rely on the RADIUS-based protocol for device and/or user authentication should update their software and configuration to a secure form of the protocol for both clients and servers. This can be done by enforcing TLS or DTLS encryption to secure the communications between the RADIUS client and server. Where possible, network isolation and secure VPN tunnel communications should be enforced for the RADIUS protocol to restrict access to these network resources from untrusted sources. https://blog.cloudflare.com/radius-udp-vulnerable-md5-attack/ provides additional detail, including: The IETF is an important venue for standardizing network protocols like RADIUS. The IETF’s radext working group is currently considering an initiative to deprecate RADIUS/UDP and create a “standards track” specification of RADIUS over TLS or DTLS, that should help accelerate the deployment of RADIUS/TLS in the field. We hope that our work will accelerate the community’s ongoing efforts to secure RADIUS and reduce its reliance on MD5. https://www.blastradius.fail/ has further details from the researchers.

https://www.freeradius.org/security/ provides a lengthy response from the FreeRADIUS maintainers.

-- -Alan Coopersmith- alan.coopersmith () oracle com Oracle Solaris Engineering - https://blogs.oracle.com/solaris