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SYNTHESIS OF THE VULNERABILITY

A local attacker can use a long path in order to stop applications
using the fts_* functions of the libc.

Gravity: 1/4

Consequences: denial of service of service

Provenance: user shell

Means of attack: 1 attack

Ability of attacker: technician (2/4)

Confidence: confirmed by the editor (5/5)

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

Creation date: 06/03/2009

IMPACTED PRODUCTS

– OpenBSD

DESCRIPTION OF THE VULNERABILITY

Functions in the fts (fts_open, fts_read, etc.) family are used to
go through a directory hierarchy.

They use the _ftsent structure to store information on a file.
This structure has a field named fts_level, which contains the
depth level where the file was found (number of went through
directories). The fts_level field is of short type (16 bit,
maximum 64k).

However, the OpenBSD implementation of fts does not check if the
depth is over 64k. A negative value is then used, which creates an
error.

A local attacker can therefore use a long path in order to stop
applications using the fts_* functions of the libc.

CHARACTERISTICS

Identifiers: BID-34008, CVE-2009-0537, VIGILANCE-VUL-8517

http://vigilance.fr/vulnerability/OpenBSD-denial-of-service-via-fts-8517