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Family: Gentoo Local Security Checks --> Category: infos
[GLSA-200402-07] Clam Antivirus DoS vulnerability Vulnerability Scan
Vulnerability Scan Summary
Clam Antivirus DoS vulnerability
Detailed Explanation for this Vulnerability Test
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 allowed 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"
Threat Level: Medium
Click HERE for more information and discussions on this network vulnerability scan.
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