ZDI-11-136 (formerly ZDI-CAN-1022): IBM Tivoli Directory Server ibmslapd.exe SASL Bind Request Remote Code Execution Vulnerability
April 18, 2011
-- CVE ID: CVE-2011-1206
-- CVSS: 10, (AV:N/AC:L/Au:N/C:C/I:C/A:C)
-- Affected Vendors: IBM
-- Affected Products: IBM Tivoli Directory Server
-- TippingPoint(TM) IPS Customer Protection: TippingPoint IPS customers have been protected against this vulnerability by Digital Vaccine protection filter ID 11092. For further product information on the TippingPoint IPS, visit:
-- Vulnerability Details: This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of IBM Tivoli Directory Server. Authentication is not required to exploit this vulnerability.
The specific flaw exists in how ibmslapd.exe handles LDAP CRAM-MD5 packets. ibmslapd.exe listens by default on port TCP 389. When the process receives an LDAP CRAM-MD5 packet, it uses libibmldap.dll to handle the allocation of a buffer for the packet data. A specially crafted packet can cause the ber_get_int function to allocate a buffer that is too small to fit the packet data, causing a subsequent stack-based buffer overflow. This can be leveraged by a remote attacker to execute arbitrary code under the context of the SYSTEM user.
-- Vendor Response: IBM has issued an update to correct this vulnerability. More details can be found at:
-- Disclosure Timeline: 2011-02-17 - Vulnerability reported to vendor 2011-04-18 - Coordinated public release of advisory
-- Credit: This vulnerability was discovered by: * Francis Provencher for Protek Research Lab's
-- About the Zero Day Initiative (ZDI): Established by TippingPoint, The Zero Day Initiative (ZDI) represents a best-of-breed model for rewarding security researchers for responsibly disclosing discovered vulnerabilities.
Researchers interested in getting paid for their security research through the ZDI can find more information and sign-up at:
The ZDI is unique in how the acquired vulnerability information is used. TippingPoint does not re-sell the vulnerability details or any exploit code. Instead, upon notifying the affected product vendor, TippingPoint provides its customers with zero day protection through its intrusion prevention technology. Explicit details regarding the specifics of the vulnerability are not exposed to any parties until an official vendor patch is publicly available. Furthermore, with the altruistic aim of helping to secure a broader user base, TippingPoint provides this vulnerability information confidentially to security vendors (including competitors) who have a vulnerability protection or mitigation product.
Our vulnerability disclosure policy is available online at:
Follow the ZDI on Twitter: