.:: SUMMARY Novell GroupWise Client Remote Buffer Overflow Version: GroupWise 6.5.3, It is suspected that all previous versions of Groupwise Client are vulnerable. .:: BACKGROUND GroupWise Client is Novell's premier Intranet/Internet GroupWare solution for platform Windows. More info: http://www.novell.com .:: DESCRIPTION This issue is due to a failure of the application to securely parse the file that contain the labels of different views. To reproduce this, we have to modify the ofview file that corresponds to the language of the postoffices. In spanish lenguage it is GWVW02ES.INI ([POSTOFFICES]\ofviews\win\GWVW02ES.INI) For example, we take the section [Group Task] and set the label ES02TKS.VEW with the value ("A" x 174). Then, when we open the application client and make the authentication, after that occur the buffer overflow. Information of Registers: EAX 00000001 ECX 7FFDE000 EDX 00E80608 EBX 41414141 ESP 0012F74C EBP 0012F7B0 ESI 00E80000 EDI 41414139 EIP 78495BA9 ntdll.78495BA9 C 0 ES 0023 32bit 0(FFFFFFFF) P 1 CS 001B 32bit 0(FFFFFFFF) A 0 SS 0023 32bit 0(FFFFFFFF) Z 1 DS 0023 32bit 0(FFFFFFFF) S 0 FS 0038 32bit 7FFDE000(FFF) T 0 GS 0000 NULL D 0 O 0 LastErr ERROR_SUCCESS (00000000) EFL 00010246 (NO,NB,E,BE,NS,PE,GE,LE) ST0 empty - NAN FFFF FFF8FCF8 FFF8FCF8 ST1 empty - ??? FFFF 00000000 00000000 ST2 empty - ??? FFFF 00FE00F7 00FB00F7 ST3 empty - ??? FFFF 00FE00F7 00FB00F7 ST4 empty - NAN FFFF FFF8FCF8 FFF8FCF8 ST5 empty - ??? FFFF 00FF00F8 00FC00F8 ST6 empty - ??? FFFF 00000000 00000000 ST7 empty 256.00000000000000000 3 2 1 0 E S P U O Z D I FST 0000 Cond 0 0 0 0 Err 0 0 0 0 0 0 0 0 (GT) FCW 027F Prec NEAR,53 Mask 1 1 1 1 1 1 Asm code line: 78495BA9 0FB707 MOVZX EAX,WORD PTR DS:[EDI] If a attacker have access to the postoffices and put a evil GWVW02??.INI, He could have the posibilite of compromise every user that use the Novell GroupWise Windows Application. .:: VENDOR RESPONSE Vendor advisory: http://support.novell.com/cgi-bin/search/searchtid.cgi?/10098314.htm Vendor patch: http://support.novell.com/cgi-bin/search/searchtid.cgi?/2971927.htm .:: DISCLOSURE TIMELINE 07/05/2005 Initial vendor notification 07/06/2005 Initial vendor response 07/27/2005 Coordinated public disclosure .:: CREDIT Francisco Amato is credited with discovering this vulnerability. famato][at][infobyte][dot][com][dot][ar .:: LEGAL NOTICES Copyright (c) 2005 by [ISR] Infobyte Security Research. Permission to redistribute this alert electronically is granted as long as it is not edited in any way unless authorized by Infobyte Security Research Response. Reprinting the whole or part of this alert in any medium other than electronically requires permission from infobyte com ar 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.