iDEFENSE has identified an NTLM Buffer Overflow Vulnerability in wget/curl. This vulnerability was submitted to iDEFENSE through our Vulnerability Contributor Program:
http://www.idefense.com/poi/teams/vcp.jsp iDEFENSE Labs has validated this vulnerability and has drafted the attached advisory. In accordance with our vendor disclosure policy http://www.idefense.com/legal_disclosure.jsp We would request that you acknowledge receipt of this initial notification within five business days so that we may begin the process of coordinating an appropriate public disclosure date for this issue that will provide your company with adequate time to develop a patch or workaround to mitigate this vulnerability. If you have questions regarding this issue or require further details to assist with your own analysis, please do not hesitate to contact us. It is always our goal to coordinate on the public disclosure of patches/advisories as quickly as possible after a vulnerability is discovered. If however a reasonable timeframe cannot be agreed upon for this issue, it will be publicly released in 60 days on 12/12/2005. iDEFENSE is willing to work with a vendor to find a mutually agreeable release date beyond this timeframe so long as the vendor continues to make good faith efforts to produce patches in a timely fashion and regularly informs iDEFENSE of their progress in doing so. Please note that if the affected product is included within other applications and/or operating systems, iDEFENSE will not be coordinating disclosure of the vulnerability to affected third parties. We would ask that you handle this coordination separately. Regards, Michael Sutton Michael Sutton Director, iDEFENSE Labs iDEFENSE 1875 Campus Commons Drive, Suite 210 Reston, VA 20191 direct: 703.480.5628 voice: 703.390.1230 fax: 703.390.9456 [EMAIL PROTECTED] www.idefense.com
Multiple Vendor wget/curl NTLM Username Buffer Overflow Vulnerability iDEFENSE Security Advisory XX.XX.05 http://www.idefense.com/application/poi/display?type=vulnerabilities MMM DD, 2005 I. BACKGROUND GNU Wget is a free software package for retrieving files using HTTP, HTTPS and FTP, the most widely-used Internet protocols. It is a non-interactive commandline tool, so it may easily be called from scripts, cron jobs, terminals without X-Windows support, etc. More information on Wget is available from the vendor website: http://www.gnu.org/software/wget/wget.html curl is a command line tool for transferring files with URL syntax, supporting FTP, FTPS, HTTP, HTTPS, GOPHER, TELNET, DICT, FILE and LDAP. Curl supports HTTPS certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, cookies, user+password authentication (Basic, Digest, NTLM, Negotiate, kerberos...), file transfer resume, proxy tunneling and a busload of other useful tricks. More information on curl is available from the vendor website: http://curl.haxx.se/ II. DESCRIPTION Remote exploitation of a buffer overflow vulnerability in multiple vendor's implementations of curl and wget allows attackers to execute arbitrary code. The vulnerability specifically exists due to insufficent bounds checking on user-supplied data supplied to a memory copy operation. The memcpy() of the supplied ntlm username to ntlmbuf shown below results in a stack overflow: http-ntlm.c in ntlm_output() on line 532: /* size is now 64 */ size=64; ntlmbuf[62]=ntlmbuf[63]=0; memcpy(&ntlmbuf[size], domain, domlen); size += domlen; memcpy(&ntlmbuf[size], usr, userlen); size += userlen; The resulting stack overflow can be leveraged to gain arbitrary code execution with user privileges. III. ANALYSIS Successful exploitation of the vulnerability allows remote attackers to execute arbitrary code with permissions of the http client process. User interaction is required. Exploitation requires a user to use one of the affected clients to connect to a malicious website. This vulnerability affects both wget and curl clients similarly because wget 1.10 adopted the curl ntlm authentication source code into its own codebase. The described vulnerability requires that ntlm authentication is enabled in the affected client versions. A factor that somewhat increases the risk of this vulnerability is that a client can be forced to reconnect using ntlm authentication by issuing a HTTP 302 REDIRECT command to the connecting client. IV. DETECTION iDEFENSE Labs has confirmed the following software versions are vulnerable: wget 1.10 curl 7.13.2 libcurl 7.13.2 V. WORKAROUND As a workaround solution, disable ntlm support in wget and curl installations until the vendor releases a patch. VI. VENDOR RESPONSE [Quoted vendor response if available. Otherwise include vendor fix details.] VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CAN-2005-XXXX to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems. [OR] A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 10/22/2005 Initial vendor notification XX/XX/2005 Initial vendor response XX/XX/2005 Coordinated public disclosure IX. CREDIT The discoverer of this vulnerability wishes to remain anonymous. Get paid for vulnerability research http://www.idefense.com/poi/teams/vcp.jsp Free tools, research and upcoming events http://labs.idefense.com X. LEGAL NOTICES Copyright © 2005 iDEFENSE, Inc. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDEFENSE. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please email [EMAIL PROTECTED] for permission. Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.