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Home >> Browse Vulnerability Assessment Database >> Gentoo Local Security Checks >> [GLSA-200402-07] Clam Antivirus DoS vulnerability

Vulnerability Assessment Details

[GLSA-200402-07] Clam Antivirus DoS vulnerability

Vulnerability Assessment Summary
Clam Antivirus DoS vulnerability

Detailed Explanation for this Vulnerability Assessment
The remote host is affected by the vulnerability described in GLSA-200402-07
(Clam Antivirus DoS vulnerability)

Oliver Eikemeier of Fillmore Labs discovered the overflow in Clam AV 0.65
when it handled malformed UUEncoded messages, causing the daemon to shut
down.
The problem originated in libclamav which calculates the line length of an
uuencoded message by taking the ASCII value of the first character minus 64
while doing an assertion if the length is not in the permited range,
effectively terminating the calling program as clamav would not be
available.

Impact

A malformed message such as the one below would cause a denial of service,
and depending on the server configuration this may impact other daemons
relying on Clam AV in a fatal manner.
To exploit the vulnerability, you can add the following to ~/clamtest.mbox:
From -
begin 644 byebye
byebye
end
Then do "clamscan --mbox -v ~/clamtest.mbox" or "clamdscan
-v ~/clamtest.mbox
ps ax | grep clam": the former will cause an
assertion and a segmentation fault, the latter would cause the daemon to
shut down.

Workaround

There is no immediate workaround, a software upgrade is required.

Solution:
All users are urged to upgrade their Clam AV installations to Clam AV 0.67:
# emerge sync
# emerge -pv ">=net-mail/clamav-0.6.7"
# emerge ">=net-mail/clamav-0.6.7"

Network Security Threat Level: Medium

Networks Security ID:

Vulnerability Assessment Copyright: (C) 2005 Michel Arboi

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