Title: NASA Common Data Format remote buffer overflow(s)
Advisory ID: INFIGO-2009-07-09
Advisory URL: http://www.infigo.hr/en/in_focus/advisories/INFIGO-2009-07-09
Impact: Remote code execution
Risk Level: High
Vulnerability Type: Remote
The vulnerability exists in the ReadAEDRList64() function. This function
is used to read a list of attribute entries from a CDF file.
The attribute entries are stored in a list indexed by the entry number.
Various other memory corruption vulnerabilities have been identified
in SearchForRecord_r_64(), LastRecord64(), CDFsel64() and other functions.
In cooperation with the vendor all identified vulnerable function have
been fixed, and a proper validation module was developed to verify CDF
files before processing them.
The vulnerabilities has been identified in the latest available CDF
version 3.2.4. Previous versions are believed to be vulnerable as well
Steps to Reproduce:
The vendor has addressed vulnerabilities on 20.7.2009. with CDF
library version 3.3. New CDF library 3.3 has 'cdfvalidate' module
that will validate CDF files for potential malformed values.
New version is available at http://cdf.gsfc.nasa.gov/.
STATICforIDL CDFstatus ReadAEDRList64 (vFILE *fp,
struct AEDRstructExt64 ***AEDRList,
struct AEDRstructExt64 *TempAEDR;
Int32 LastAEDRNum = -1;
 *AEDRList = cdf_AllocateMemory((MaxEntry + 1) *
sizeof(struct AEDRstructExt64**), NULL);
while (NxtAEDR != 0 && LastAEDRNum != MaxEntry)
 TempAEDR = cdf_AllocateMemory(sizeof(struct AEDRstructExt64), NULL);
 if (!Read32_64(fp,&(TempAEDR->AEDR.Num))) return CRE;
 (*AEDRList)[TempAEDR->AEDR.Num] = TempAEDR;
The code marked as  creates an array of AEDRstructExt64 structures,
allocated on the heap and assigned to the AEDRList variable. The TempAEDR
structure  is also allocated on the heap. It is further used in the
while() loop to read the attributes from the CDF file that is being
The Read32_64() function  is used to read an integer from the
CDF file stream and store it in the TempAEDR->AEDR.Num. At  this value
is used as the index that specifies where in the AEDRList the address of
the TempAEDR structure is stored.
This is where the vulnerability exists as the code performs no sanity
checks on the TempAEDR->AEDR.Num value.
In other words, if the CDF file contains a value that is higher than the
number of allocated AEDRList entries, a malicious CDF file can overwrite
arbitrary heap data after the AEDRList array. The value that will be
written is the address of the TempAEDR structure. This can be further
exploited as the attacker can control the content of the TempAEDR
structure, in which malicious code can be embedded.
As the TempAEDR->AEDR.Num is used as the index, the attacker can write 4
bytes to an address higher than the AEDRList's address. Since this index
is added to the AEDRList address, an attacker can also specify a large
value which allows him to overflow the integer in the adding calculation,
effectively writing to any address mapped by the process.
Other protection mechanisms, such as ASLR, could make this exploitation
method less reliable.
bumped to 3.3 in cvs. thanks.
Arches, please test and mark stable:
Target keywords: "amd64 ppc x86"
CVE reqeusted and draft filed.
Multiple buffer overflows in NASA Common Data Format (CDF) allow
context-dependent attackers to execute arbitrary code, as
demonstrated using (1) an array index error in the ReadAEDRList64
function, and other errors in the (2) SearchForRecord_r_64, (3)
LastRecord64, (4) CDFsel64, and other unspecified functions.