=========================================================================== A U S C E R T A L E R T AL-2004.07 -- AUSCERT ALERT New Bagle.Q Worm Spreading Rapidly 18 March 2004 =========================================================================== AusCERT is aware of local activity by a new type of mass-mailing worm. Dubbed Bagle.Q, this worm exploits a recent vulnerability in the Microsoft Internet Explorer engine to allow infection without active user intervention and without including the virus executable in the email message. The worm has two stages of execution: 1. An email message is received with the following (example) body:

2. Upon preview within vulnerable mail applications (eg Microsoft Outlook and Microsoft Outlook Express), the virus/worm body is downloaded via HTTP from the IP address in the DATA field of the HTML message. Machines infected with the worm repeat the process, using the worm's inbuilt SMTP engine to send the message to addresses harvested from various files on the computer, and constructed with a DATA field containing either the infected machine's IP address or one from a hard-coded list of IP addresses in the worm itself. The vulnerability exploited by this worm is Microsoft Security Bulletin MS03-032 [2][3]. System administrators should apply the measures described in that advisory to correct the vulnerability, either manually or by using Windows Update. Anti-virus vendors will have updated signature files available soon, and these should be applied as soon as possible. It appears, so far, that the URL used to download the viral executable consistently uses TCP port 81, so sites may wish to block that port outbound as a stop-gap measure while more permanent measures are prepared. However, as some legitimate web sites utilise this port, this measure should be regarded as temporary only. References: [1] Protecting your computer from malicious code http://www.auscert.org.au/3352 [2] Microsoft Security Bulletin MS03-032 http://www.microsoft.com/technet/security/bulletin/MS03-032.mspx [3] AusCERT External Security Bulletin ESB-2003.0588 http://www.auscert.org.au/3371 [4] Sophos http://www.sophos.com/virusinfo/analyses/w32bagleq.html [5] Computer Associates http://www3.ca.com/threatinfo/virusinfo/virus.aspx?id=38599 [6] McAfee http://us.mcafee.com/virusInfo/default.asp?id=description&virus_k=101108 [7] Trend Micro http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=PE_BAGLE.Q&VSect=T - --------------------------------------------------------------------------- The AusCERT team has made every effort to ensure that the information contained in this security bulletin is accurate at the time of publication. However, the decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation\'s site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. If you believe that your computer system has been compromised or attacked in any way, we encourage you to let us know by completing the secure National IT Incident Reporting Form at: http://www.auscert.org.au/render.html?it=3192 AusCERT maintains a World Wide Web service which is found on: http://www.auscert.org.au. Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. Postal: Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 AUSTRALIA ===========================================================================