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Sid 1-45108

Message

PROTOCOL-RPC XDR string allocation denial of service attempt

Summary

This event is generated when an attacker attempts to exploit a denial of service vulnerability in rpcbind.

Impact

Denial of service

CVE-2017-8779:

CVSS base score 7.5

CVSS impact score 3.6

CVSS exploitability score 3.9

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Detailed information

Rule checks for a DoS attempt against rpcbind. CVE-2017-8779: rpcbind through 0.2.4, LIBTIRPC through 1.0.1 and 1.0.2-rc through 1.0.2-rc3, and NTIRPC through 1.4.3 do not consider the maximum RPC data size during memory allocation for XDR strings, which allows remote attackers to cause a denial of service (memory consumption with no subsequent free) via a crafted UDP packet to port 111, aka rpcbomb.

Affected systems

  • libtirpc_project libtirpc 1.0.1
  • ntirpc_project ntirpc 1.4.3
  • rpcbind_project rpcbind 0.2.4

Ease of attack

Simple; Metasploit module publicly-available

False positives

Not known

False negatives

Not known

Corrective action

Contributors

  • Cisco's Talos Intelligence Group

Additional References