Date: Wed, 23 Apr 2003 12:04:43 -0500
From: "Neulinger, Nathan" <nneul@....edu>
To: "b0f www.b0f.net" <b0fnet@...oo.com>, <bugtraq@...urityfocus.com>
Subject: RE: [cgiwrap-users] RE:  Format strings vuln in CGIwrap


In any case, I've changed this in cvs so as to avoid setting off any
future false-alarms. 

------------------------------------------------------------
Nathan Neulinger                       EMail:  nneul@....edu
University of Missouri - Rolla         Phone: (573) 341-4841
Computing Services                       Fax: (573) 341-4216


> -----Original Message-----
> From: Neulinger, Nathan 
> Sent: Wednesday, April 23, 2003 11:59 AM
> To: b0f www.b0f.net; bugtraq@...urityfocus.com
> Cc: cgiwrap-users@...ts.sourceforge.net
> Subject: [cgiwrap-users] RE: Format strings vuln in CGIwrap
> 
> 
> This is not a security problem. This is a case of using an automated
> tool to find these vulnerabilites and not attempting to understand the
> code itself. 
> 
> Nowhere in the code is MSG_Error_General() passed anything 
> other than a
> static compiled-into-the-executable string. It's purely a utility
> function to wrap common error text/footer/etc. around a 
> generic string.
> 
> -- Nathan
> 
> ------------------------------------------------------------
> Nathan Neulinger                       EMail:  nneul@....edu
> University of Missouri - Rolla         Phone: (573) 341-4841
> Computing Services                       Fax: (573) 341-4216
> 
> 
> > -----Original Message-----
> > From: security-bounces+nneul=umr.edu@...ts.umr.edu 
> > [mailto:security-bounces+nneul=umr.edu@...ts.umr.edu] On 
> > Behalf Of b0f www.b0f.net
> > Sent: Wednesday, April 23, 2003 11:06 AM
> > To: bugtraq@...urityfocus.com
> > Subject: Format strings vuln in CGIwrap
> > 
> > 
> > 
> > 
> > A locally and possibly remotely exploitable format
> > strings bug exists 
> > in cgiwrap available from  
> > http://cgiwrap.sourceforge.net/
> > http://sourceforge.net/projects/cgiwrap
> > http://www.freebsd.org/ports/security.html 
> > 
> > I. BACKGROUND
> > 
> > This is CGIWrap - a gateway that allows more secure
> > user access to
> > CGI programs on an HTTPd server than is provided by the
> > http server
> > itself. The primary function of CGIWrap is to make
> > certain that
> > any CGI script runs with the permissions of the user
> > who installed
> > it, and not those of the server.
> > 
> > CGIWrap works with NCSA httpd, Apache, CERN httpd,
> > NetSite Commerce
> > and Communications servers, and probably any other Unix
> > based web
> > server software that supports CGI.
> > 
> > II. DESCRIPTION
> > 
> > On line 91 of msgs.c the printf() function is used
> > incorrectly. Which 
> > results
> > in a format strings vulnerability.
> > <snip>
> > void MSG_Error_General(char *message)
> > {
> >         MSG_Header("CGIWrap Error", message);
> >         printf(message); 
> >         MSG_Footer();
> >         exit(1);
> > }
> > </snip>
> > 
> > The binaries in cgiwrap, (cgiwrap and nph-cgiwrap) are
> > installed setuid 
> > root.
> > Thus could make this format problem exploitable locally
> > to gain root 
> > privs or
> > possably remotely to gain root or the privs of the user
> > who owns the cgi 
> > script.
> > 
> > III. ANALYSIS
> > An attacker could exploit this issue to escalate privs
> > locally or 
> > remotely on
> > a server running cgiwrap.
> > 
> > IV. DETECTION
> > 
> > This is vulnerable in the latest version of cgiwrap
> > version 3.7.1 and 
> > properly
> > older versions(not checked). It would be exploitable on
> > any Linux/Unix 
> > based OS
> > running cgiwrap 
> > 
> > V. VENDOR
> > The vendor has not been contacted about this issue.
> > 
> > Regards
> > b0f  (Alan M)
> > www.b0f.net
> > _______________________________________________
> > UMR Security List Exploder
> > security@...ts.umr.edu
> > https://lists.umr.edu/mailman/listinfo/security
> > 
> 
> 
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