Actu
Vigil@nce - ModSecurity: denial of service via forceRequestBodyVariable
June 2013 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
When the forceRequestBodyVariable option of ModSecurity is
enabled, an attacker can send a query with an unknown Content-Type
header, to dereference a NULL pointer, in order to trigger a
denial of service.
Impacted products: Apache httpd, Fedora
Severity: 2/4
Creation date: 28/05/2013
DESCRIPTION OF THE VULNERABILITY
The ModSecurity module can be installed on Apache httpd. It
contains security rules, in order to block malicious queries.
The forceRequestBodyVariable option forces the generation of the
REQUEST_BODY variable. In this case, ModSecurity uses
msr->msc_reqbody_chunks->elts to generate the HTTP body. However,
if the Content-Type header is unknown, and if the body size is
greater than SecRequestBodyInMemoryLimit, the
msr->msc_reqbody_chunks field is NULL.
When the forceRequestBodyVariable option of ModSecurity is
enabled, an attacker can therefore send a query with an unknown
Content-Type header, to dereference a NULL pointer, in order to
trigger a denial of service.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/ModSecurity-denial-of-service-via-forceRequestBodyVariable-12864
