|发布时间 :2004-10-20 00:00:00|
|修订时间 :2017-07-10 21:29:56|
[原文]Multiple content security gateway and antivirus products allow remote attackers to bypass content restrictions via MIME encapsulation that uses RFC822 comment fields, which may be interpreted as other fields by mail clients.
- CVSS (基础分值)
- CPE (受影响的平台与产品)
- OVAL (用于检测的技术细节)
(UNKNOWN) BUGTRAQ 20040914 Corsaire Security Advisory - Multiple vendor MIME RFC822 comment issue
(VENDOR_ADVISORY) MISC http://www.uniras.gov.uk/vuls/2004/380375/mime.htm
(UNKNOWN) XF mime-rfc822-filtering-bypass(17332)
|2004-10-20 00:00:00||2006-08-22 00:00:00|
plDaniels have released ripMime 220.127.116.11 to address this issue.
F-Secure will be releasing Internet Gatekeeper 6.41 to address this issue in Q4/04.
plDaniels ripMime 1.2 .0
plDaniels ripMime 1.2.1
plDaniels ripMime 1.2.2
plDaniels ripMime 1.2.3
plDaniels ripMime 1.2.4
plDaniels ripMime 1.2.5
plDaniels ripMime 1.2.6
plDaniels ripMime 1.2.7
plDaniels ripMime 1.3.2 .3
plDaniels ripMime 1.3.2 .0
plDaniels ripMime 1.3.2 .2
- 漏洞信息 (F34359)
|Corsaire Security Advisory 2003-08-04.9 (PacketStormID:F34359)|
|Martin O'Neal,Corsaire corsaire.com|
Corsaire Security Advisory - By using malformed MIME encapsulation techniques centered on the presence of fields containing an RFC822 comment, embedded file attachment blocking functionality can be evaded.
-- Corsaire Security Advisory -- Title: Multiple vendor MIME RFC822 comment issue Date: 04.08.03 Application: various Environment: various Author: Martin O'Neal [email@example.com] Audience: General distribution Reference: c030804-009 -- Scope -- The aim of this document is to clearly define a MIME content evasion issue that affects a variety of products including; browsers, proxy servers, email clients, content security gateways and antivirus products. -- History -- Discovered: 04.08.03 (Martin O'Neal) NISCC notified: 19.02.04 Document released: 13.09.04 -- Overview -- There are a number of content security gateway and antivirus products available that provide policy based security functionality. Part of this functionality allows the products to block embedded file attachments based on their specific content type, such as executables or those containing viruses. However, by using malformed MIME encapsulation techniques centred on the presence of fields containing an RFC822 comment, this functionality can be evaded. -- Analysis -- The MIME standards are intended to provide a common mechanism to exchange data between systems and are used extensively by protocols such as HTTP and SMTP. The structure of a MIME message is defined in RFC2045 , which in turn makes use of concepts introduced in RFC822  (superseded by RFC2822 ). The standards define a range of fields that control how data is encoded within the transport, and how it should be interpreted by the receiving agent. RFC822  states "A comment is a set of ASCII characters, which is enclosed in matching parentheses and which is not within a quoted- string. The comment construct permits message originators to add text which will be useful for human readers, but which will be ignored by the formal semantics. Comments should be retained while the message is subject to interpretation according to this standard. However, comments must NOT be included in other cases, such as during protocol exchanges with mail servers". The implementation of the commenting standard has not been universal by all of the vendors. For many products, such as email clients and browsers, this scope for variation might only result in some unreliable behaviour. However, for a collection of security products, being unaware of the various ways that the standard has been implemented can lead to more serious results, as the products may fail to detect a threat within the data stream. When a receiving agent is presented with a MIME message that contains an unexpected RFC822 comment, it tends to respond in one of three broad ways: - It identifies the MIME message as malformed and blocks it. - It fails to interpret the MIME field (or message). - It correctly interprets the MIME field (or message). The first of the three would be the correct behaviour for a security conscious product, but based on empirical research this is not the common result for a number of scenarios. The RFC822 comment issue has been observed to affect many of the security products. To use this issue as an attack vector, all that is required is to identify a target that has a client agent that successfully interprets the RFC822 comment correctly, where any security products that protect it do not. -- Recommendations -- To be effective tools, the security products must not only be able to process encoding techniques implemented as per the relevant standard, but also common misinterpretations and deliberate corruptions. As an ongoing process, a study project should be undertaken by the vendors to identify applications that routinely decode MIME objects and have a liberal interpretation of the MIME standard. NISCC have produced a document consolidating a number of vendor statements on these issues . Contact your vendor directly to establish whether you are affected by these issues. -- Background -- This issue was discovered using a custom SMTP/HTTP vulnerability analysis tool developed by Corsaire's security assessment team. This tool is not available publicly, but is an example of the specialist approach used by Corsaire's consultants as part of a commercial security assessment. To find out more about the cutting edge services provided by Corsaire simply visit our web site at http://www.corsaire.com -- CVE -- The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2004-0162 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardises names for security problems. -- References --  http://www.faqs.org/rfcs/rfc2045.html  http://www.faqs.org/rfcs/rfc822.html  http://www.faqs.org/rfcs/rfc2822.html  http://www.uniras.gov.uk/vuls/2004/380375/mime.htm -- Revision -- a. Initial release. b. Added CVE reference. c. Released. -- Distribution -- This security advisory may be freely distributed, provided that it remains unaltered and in its original form. -- Disclaimer -- The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Corsaire accepts no responsibility for any damage caused by the use or misuse of this information. -- About Corsaire -- Corsaire are a leading information security consultancy, founded in 1997 in Guildford, Surrey, UK. Corsaire bring innovation, integrity and analytical rigour to every job, which means fast and dramatic security performance improvements. Our services centre on the delivery of information security planning, assessment, implementation, management and vulnerability research. A free guide to selecting a security assessment supplier is available at http://www.penetration-testing.com Copyright 2003 Corsaire Limited. All rights reserved.
|Multiple Content Monitor Software RFC822 Comment Field MIME Encapsulation Filter Bypass|
Unknown or Incomplete
Unknown or Incomplete
|Unknown or Incomplete|