ZyXEL Prestige SDSL Router Can Be Crashed By Remote Users Sending Malformed Packets
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SecurityTracker Alert ID: 1002977 |
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SecurityTracker URL: http://securitytracker.com/id/1002977
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CVE Reference:
GENERIC-MAP-NOMATCH
(Links to External Site)
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Date: Dec 14 2001
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Impact:
Denial of service via network
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Version(s): Prestige 681, 1600; possibly others
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Description:
A denial of service vulnerability has been reported in ZyXEL's Prestige SDSL routers. A remote user can cause the router to hang by sending malformed packets.
It is reported that a remote user can send certain malformed packets to the router on the DSL-interface side of the router to cause it to hang. This reportedly cannot be triggered from the internal Ethernet interface side of the router. When the vulnerability is triggered, ZyNOS apparently reports that the line is synchronizing. It may take between 2 and 3 mintues before the link comes back up and operations return to normal.
The nature of the malformed packets required to exploit this flaw was not disclosed.
The vendor has reportedly been notified.
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Impact:
A remote user can cause the router to stop processing traffic for several minutes.
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Solution:
No solution was available at the time of this entry.
The author of the report presents a workaround:
"The workaround is to switch off routing and put device in bridging mode."
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Vendor URL: www.zyxel.com/ (Links to External Site)
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Cause:
Exception handling error
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Underlying OS:
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Message History:
None.
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Source Message Contents
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Date: Fri, 14 Dec 2001 12:08:59 +0100
Subject: Zyxel Prestige 681 and 1600 (possibly other?) remote DoS
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Hello,
Zyxel Prestige 681 SDSL router is vulnerable to *remote* denial of service.
By sending malformed packets, it is possible to bring down DSL link for few
minutes. The problem persists only if packets come from DSL interface, not
from Ethernet. ZyNOS reports that line is synchronizing and it takes about
2-3 minutes before link is up.
The workaround is to switch off routing and put device in bridging mode.
Zyxel support has been notified, I won't release details of attack, until
ZyNOS will be patched.
--
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