CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
EPSS
Percentile
91.3%
The Microsoft Exchange LDAP Service contains vulnerabilities that may allow denial-of-service attacks. These vulnerabilities were revealed using the PROTOS LDAPv3 test suite and are documented in CERT Advisory CA-2001-18. If your site uses this product, the CERT/CC encourages you to follow the advice provided below.
The LDAP Service components of Microsoft Exchange 5.5 and Exchange 2000 contain vulnerabilities that cause affected LDAP servers to freeze in response to malformed LDAP requests generated by the PROTOS test suite. This only affects the LDAP service; all other Exchange services, including mail handling, continue normally.
Although these products were not included in OUSPG’s initial testing, subsequent informal testing revealed that the LDAP service of Microsoft Exchange became unresponsive while processing test cases containing exceptional BER encodings for the LDAP filter type field.
These vulnerabilities allow a remote attacker to crash the LDAP component of vulnerable Exchange 5.5 and Exchange 2000 servers, resulting in a denial-of-service condition within the LDAP component.
Apply a patch from your vendor
Please consult the vendor section for vendor-specific information on addressing this vulnerability.
Block access to directory services at network perimeter
As a temporary measure, it is possible to limit the scope of these vulnerabilities by blocking access to directory services at the network perimeter. Please note that this workaround does not protect vulnerable products from internal attacks.
ldap 389/tcp # Lightweight Directory Access Protocol
ldap 389/udp # Lightweight Directory Access Protocol
ldaps 636/tcp # ldap protocol over TLS/SSL (was sldap)
ldaps 636/udp # ldap protocol over TLS/SSL (was sldap)
Disable anonymous LDAP access
Microsoft has reported that “It is important to note that this issue can be mitigated by disabling anonymous authentication.”
763400
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Notified: May 31, 2001 Updated: July 16, 2001
Affected
Microsoft is developing a hotfix for this issue which will be available shortly.
Customers can obtain this hotfix by contacting Product Support Services at no charge and asking for Q303448 and Q303450. Information on contacting Microsoft Product Support Services can be found at
<http://www.microsoft.com/support/>
The vendor has not provided us with any further information regarding this vulnerability.
The CERT/CC has no additional comments at this time.
If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23763400 Feedback>).
Group | Score | Vector |
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Base | ||
Temporal | ||
Environmental |
The CERT Coordination Center thanks the Oulu University Secure Programming Group for reporting these vulnerabilities to us, for their detailed technical analyses, and for their assistance in preparing this document.
This document was written by Jeffrey P. Lanza.
CVE IDs: | CVE-2001-1319 |
---|---|
CERT Advisory: | CA-2001-18 Severity Metric: |