Severity: 1/4

Consequences: data reading, data creation/edition

Provenance: user account

Means of attack: no proof of concept, no attack

Ability of attacker: expert (4/4)

Confidence: confirmed by the editor (5/5)

Diffusion of the vulnerable configuration: high (3/3)

Creation date: 16/06/2009

IMPACTED PRODUCTS

 Apache httpd
 Debian Linux

DESCRIPTION OF THE VULNERABILITY

The AllowOverride directive of the Apache httpd configuration file indicates if directives located in a .htaccess file are honoured. For example:
AllowOverride None : nothing is allowed
AllowOverride All : everything is allowed
AllowOverride Option : directives changing directory options are allowed

Since Apache httpd version 2.2, the Option parameter of the AllowOverride directive can restrict the list of allowed options. For example:
AllowOverride Options=Indexes,IncludesNOEXEC

However, due to a logic error, when at least one option is indicated in AllowOverride, they are all allowed (as it was the case before Apache httpd < 2.2).

An attacker can therefore for example enable the "Includes" option in a .htaccess file in order to use "#exec cmd" and "#exec cgi" commands.

CHARACTERISTICS

Identifiers: 44262, DSA 1816-1, VIGILANCE-VUL-8798

http://vigilance.fr/vulnerability/Apache-httpd-bypassing-AllowOverride-8798