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Core Security Technologies - CoreLabs Advisory
http://www.coresecurity.com/corelabs/
NASA BigView Stack Buffer Overflow
*Advisory Information*
Title: NASA BigView Stack Buffer Overflow
Advisory ID: CORE-2008-0425
Advisory URL: http://www.coresecurity.com/?action=item&id=2304
Date published: 2008-06-04
Date of last update: 2008-06-03
Vendors contacted: NASA Ames Research Center
Release mode: Coordinated release
*Vulnerability Information*
Class: Stack Overflow
Remotely Exploitable: Yes (client side)
Locally Exploitable: No
Bugtraq ID: 29517
CVE Name: CVE-2008-2542
*Vulnerability Description*
NASA BigView [1] allows for interactive panning and zooming of images of
arbitrary size on desktop PCs running Linux. Using this software, one
can explore (on relatively modest machines) images such as the Mars
Orbiter Camera mosaic [92160x33280 pixels].
The BigView package suffers from a stack buffer overflow when parsing
specially crafted (invalid) PNM input files. If successful, a malicious
third party could trigger execution of arbitrary code within the context
of the application, or otherwise crash the whole application. The
vulnerability is caused due to the BigView package not properly checking
the line length of the ascii PNM input files before copying it on a
stack buffer. This can be exploited to get arbitrary code execution by
opening a specially crafted file.
Exploitation of the PNM overflow problem requires the user to explicitly
open a malicious file. The user should refrain from opening files from
untrusted third parties or accessing untrusted Web sites until the patch
is applied.
*Vulnerable Packages*
. BigView revision 1.8.
. Older BigView versions could be affected too, but they were not tested.
*Non-vulnerable Packages*
. Available through BigView website (since June 2nd 2008, see below).
*Vendor Information, Solutions and Workarounds*
The NASA BigView team has published a new version fixing this
vulnerability. The tarball is available on BigView's website:
http://opensource.arc.nasa.gov/project/bigview/
*Credits*
This vulnerability was discovered and researched by Alfredo Ortega, from
CORE IMPACT's Exploit Writing Team (EWT), Core Security Technologies.
*Technical Description / Proof of Concept Code*
The BigView package suffers from a stack buffer overflow when parsing
specially crafted (invalid) PNM input files. If successful, a malicious
third party could trigger execution of arbitrary code within the context
of the application, or otherwise crash the whole application.
The vulnerability resides in the following code at 'Ppm/ppm.C'. Here,
the function 'getline()' reads data from a file into a buffer. This is
the complete function:
/-----------
418 static void getline(int fin, char* lineBuf, int len)
419 {
420 bool done=false;
421 int index=0;
422 lineBuf[index]=' ';
423 while(! done){
424 lineBuf[index] = getOneChar(fin);
425 if( lineBuf[index]==10 ) {
426 lineBuf[index]=0;
427 done=true;
428 }
429 ++index;
430 }
431 lineBuf[index]=0;
432 }
- -----------/
Clearly the function requires the length of the destination buffer, but
it is never used internally. This function is used on the
'PPM::ppmHeader()' function, to read the header of the PPM file.
/-----------
56 PPM::ppmHeader(string filename, PPM::Format* format,
57 int* cpp, int* bpc,
58 int* sizeX, int* sizeY,
59 int* imageOffset)
60 {
61 std::ostringstream err;
62 char magic[3],lineBuf[512],junk;
63 int res,max;
.
.
.
115 while( junk == '#' ){
116 getline(fin,lineBuf,512);
117 cout << "Comment:"<