ID

VAR-200505-0908

CVE

CVE-2005-0039

TITLE

IPsec configurations may be vulnerable to information disclosure

DESCRIPTION

Certain configurations of IPsec, when using Encapsulating Security Payload (ESP) in tunnel mode, integrity protection at a higher layer, or Authentication Header (AH), allow remote attackers to decrypt IPSec communications by modifying the outer packet in ways that cause plaintext data from the inner packet to be returned in ICMP messages, as demonstrated using bit-flipping attacks and (1) Destination Address Rewriting, (2) a modified header length that causes portions of the packet to be interpreted as IP Options, or (3) a modified protocol field and source address. IPSec Confidentiality when communicating (Confidentiality) Protection only, integrity (Integrity) A vulnerability has been discovered that occurs when protection is not set. ESP Keys used (AES , DES , Triple-DES) Occurs regardless of the version or key size. The vulnerability was encrypted IPSec For communication bit-flipping By using the technique IP header ( Source address, header length, protocol field ) It is abused by tampering with the data inside. After data has been tampered with, it is sent to the sender ICMP There is a possibility that the communication contents will be acquired by receiving the error message.IPSec As a result, it is possible that important information is acquired. A vulnerability affects certain configurations of IPSec. Reports indicate that these attacks may also potentially be possible against IPSec when AH is in use, but only under certain unspecified configurations. The reported attacks take advantage of the fact that no ESP packet payload integrity checks exist when ESP is configured in the vulnerable aforementioned manner. This issue may be leveraged by an attacker to reveal plaintext IP datagrams and potentially sensitive information. Information harvested in this manner may be used to aid in further attacks. This BID will be updated as further information is made available. ---------------------------------------------------------------------- Bist Du interessiert an einem neuen Job in IT-Sicherheit? Secunia hat zwei freie Stellen als Junior und Senior Spezialist in IT- Sicherheit: http://secunia.com/secunia_vacancies/ ---------------------------------------------------------------------- TITLE: HP Tru64 UNIX IPsec Tunnel ESP Mode Encrypted Data Disclosure SECUNIA ADVISORY ID: SA16401 VERIFY ADVISORY: http://secunia.com/advisories/16401/ CRITICAL: Less critical IMPACT: Exposure of sensitive information WHERE: >From remote OPERATING SYSTEM: HP Tru64 UNIX 5.x http://secunia.com/product/2/ DESCRIPTION: HP has acknowledged a vulnerability in HP Tru64 UNIX, which can be exploited by malicious people to disclose certain sensitive information. The vulnerability affects the following supported versions: * HP Tru64 UNIX 5.1B-3 * HP Tru64 UNIX 5.1B-2/PK4 SOLUTION: Apply ERP kits. PROVIDED AND/OR DISCOVERED BY: NISCC ORIGINAL ADVISORY: HP SSRT5957: http://itrc.hp.com/service/cki/docDisplay.do?docId=HPSBTU01217 NISCC: http://www.niscc.gov.uk/niscc/docs/al-20050509-00386.html ---------------------------------------------------------------------- About: This Advisory was delivered by Secunia as a free service to help everybody keeping their systems up to date against the latest vulnerabilities. Subscribe: http://secunia.com/secunia_security_advisories/ Definitions: (Criticality, Where etc.) http://secunia.com/about_secunia_advisories/ Please Note: Secunia recommends that you verify all advisories you receive by clicking the link. Secunia NEVER sends attached files with advisories. Secunia does not advise people to install third party patches, only use those supplied by the vendor. ---------------------------------------------------------------------- Unsubscribe: Secunia Security Advisories http://secunia.com/sec_adv_unsubscribe/?email=packet%40packetstormsecurity.org ---------------------------------------------------------------------- . Some configurations using AH to provide integrity protection are also vulnerable. Some configurations using AH to provide integrity protection are also vulnerable. Impact - - ------ If exploited, it is possible for an active attacker to obtain the plaintext version of the IPsec- protected communications using only moderate effort. Severity - - -------- This is rated as high. Summary - - ------- IP Security (IPsec) is a set of protocols developed by the Internet Engineering Task Force (IETF) to support secure exchange of packets at the IP layer; IPsec has been deployed widely to implement Virtual Private Networks (VPNs). Some configurations using AH to provide integrity protection are also vulnerable. In these configurations, an attacker can modify sections of the IPsec packet, causing either the cleartext inner packet to be redirected or a network host to generate an error message. In the latter case, these errors are relayed via the Internet Control Message Protocol (ICMP); because of the design of ICMP, these messages directly reveal segments of the header and payload of the inner datagram in cleartext. An attacker who can intercept the ICMP messages can then retrieve plaintext data. The attacks have been implemented and demonstrated to work under realistic conditions. [Please note that revisions to this advisory will not be notified by email. All subscribers are advised to regularly check the UNIRAS website for updates to this notice.] Details - - ------- CVE number: CAN-2005-0039 IPsec consists of several separate protocols; these include: * Authentication Header (AH): provides authenticity guarantees for packets, by attaching strong cryptographic checksum to packets. * Encapsulating Security Payload (ESP): provides confidentiality guarantees for packets, by encrypting packets with encryption algorithms. ESP also provides optional authentication services for packets. * Internet Key Exchange (IKE): provide ways to securely negotiate shared keys. AH and ESP has two modes of use: transport mode and tunnel mode. However, without some form of integrity protection, CBC-mode encrypted data is vulnerable to modification by an active attacker. By making careful modifications to selected portions of the payload of the outer packet, an attacker can effect controlled changes to the header of the inner (encrypted) packet. The modified inner packet is subsequently processed by the IP software on the receiving security gateway or the endpoint host; the inner packet, in cleartext form, may be redirected or certain error messages may be produced and communicated by ICMP. Because of the design of ICMP, these messages directly reveal cleartext segments of the header and payload of the inner packet. If these messages can be intercepted by an attacker, then plaintext data is revealed. Attacks exploiting these vulnerabilities rely on the following: * Exploitation of the well-known bit flipping weakness of CBC mode encryption. * Lack of integrity protection for inner packets. * Interaction between IPsec processing and IP processing on security gateways and end hosts. These attacks can be fully automated so as to recover the entire contents of multiple IPsec-protected inner packets. Destination Address Rewriting * An attacker modifies the destination IP address of the encrypted (inner) packet by bit- flipping in the payload of the outer packet. * The security gateway decrypts the outer payload to recover the (modified) inner packet. * The gateway then routes the inner packet according to its (modified) destination IP address. * If successful, the "plaintext" inner datagram arrives at a host of the attacker's choice. 2. IP Options * An attacker modifies the header length of the encrypted (inner) packet by bit-flipping in the payload of the outer packet. * The security gateway decrypts the outer payload to recover the (modified) inner packet. * The gateway then performs IP options processing on the inner packet because of the modified header length, with the first part of the inner payload being interpreted as options bytes. * With some probability, options processing will result in the generation of an ICMP "parameter problem" message. * The ICMP message is routed to the now modified source address of the inner packet. * An attacker intercepts the ICMP message and retrieves the "plaintext" payload of the inner packet. 3. Protocol Field * An attacker modifies the protocol field and source address field of the encrypted (inner) packet by bit-flipping in the payload of the outer packet. * The security gateway decrypts the outer payload to recover the (modified) inner packet. * The gateway forwards the inner packet to the intended recipient. * The intended recipient inspects the protocol field of the inner packet and generates an ICMP "protocol unreachable" message. * The ICMP message is routed to the now modified source address of the inner packet. * An attacker intercepts the ICMP message and retrieves the "plaintext" payload of the inner packet. The attacks are probabilistic in nature and may need to be iterated many times in a first phase in order to be successful. Once this first phase is complete, the results can be reused to efficiently recover the contents of further inner packets. Naturally, the attacker must be able to intercept traffic passing between the security gateways in order to mount the attacks. For the second and third attacks to be successful, the attacker must be able intercept the relevant ICMP messages. Variants of these attacks in which the destination of the ICMP messages can be controlled by the attacker are also possible. Solution - - -------- Any of the following methods can be used to rectify this issue: 1. This is the recommended solution. 2. Use the AH protocol alongside ESP to provide integrity protection. However, this must be done carefully: for example, the configuration where AH in transport mode is applied end-to-end and tunnelled inside ESP is still vulnerable. 3. Remove the error reporting by restricting the generation of ICMP messages or by filtering these messages at a firewall or security gateway. Vendor Information - - ------------------ A list of vendors affected by this vulnerability is not currently available. Please visit the web site in order to check for updates. Credits - - ------- The NISCC Vulnerability Team would like to thank all vendors for their co-operation with the handling of this vulnerability. Contact Information - - ------------------- The NISCC Vulnerability Management Team can be contacted as follows: Email vulteam@niscc.gov.uk Please quote the advisory reference in the subject line Telephone +44 (0)870 487 0748 Ext 4511 Monday - Friday 08:30 - 17:00 Fax +44 (0)870 487 0749 Post Vulnerability Management Team NISCC PO Box 832 London SW1P 1BG We encourage those who wish to communicate via email to make use of our PGP key. This is available from http://www.niscc.gov.uk/niscc/publicKey2-en.pop. Please note that UK government protectively marked material should not be sent to the email address above. If you wish to be added to our email distribution list please email your request to uniras@niscc.gov.uk. What is NISCC? - - -------------- For further information regarding the UK National Infrastructure Security Co-ordination Centre, please visit http://www.niscc.gov.uk/. Reference to any specific commercial product, process, or service by trade name, trademark manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favouring by NISCC. The views and opinions of authors expressed within this notice shall not be used for advertising or product endorsement purposes. Neither shall NISCC accept responsibility for any errors or omissions contained within this advisory. In particular, they shall not be liable for any loss or damage whatsoever, arising from or in connection with the usage of information contained within this notice. C 2005 Crown Copyright <End of NISCC Vulnerability Advisory> Acknowledgements UNIRAS wishes to acknowledge the contributions of NISCC Vulnerability Team for the information contained in this Briefing. Updates This advisory contains the information released by the original author. If the vulnerability affects you, it may be prudent to retrieve the advisory from the canonical site to ensure that you receive the most current information concerning that problem. Legal Disclaimer Reference to any specific commercial product, process, or service by trade name, trademark manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favouring by UNIRAS or NISCC. The views and opinions of authors expressed within this notice shall not be used for advertising or product endorsement purposes. Neither UNIRAS or NISCC shall also accept responsibility for any errors or omissions contained within this briefing notice. In particular, they shall not be liable for any loss or damage whatsoever, arising from or in connection with the usage of information contained within this notice. FIRST UNIRAS is a member of the Forum of Incident Response and Security Teams (FIRST) and has contacts with other international Incident Response Teams (IRTs) in order to foster cooperation and coordination in incident prevention, to prompt rapid reaction to incidents, and to promote information sharing amongst its members and the community at large. SOLUTION: The vendor recommends configuring ESP to use both encryption and authentication (see vendor's advisory for more information)

AFFECTED PRODUCTS

CVSS

PROBLEMTYPE DATA

THREAT TYPE

remote

TYPE

Design Error

CONFIGURATIONS

PATCH

EXTERNAL IDS

REFERENCES

CREDITS

NISCC albatross@tim.it

SOURCES

LAST UPDATE DATE

2024-08-14T15:25:41.004000+00:00

SOURCES UPDATE DATE

SOURCES RELEASE DATE