SynopsisThe remote Ubuntu host is missing one or more security-related patches.
DescriptionDrew Yao discovered that the WEBrick HTTP server was vulnerable to cross-site scripting attacks when displaying error pages. A remote attacker could use this flaw to run arbitrary web script.
Drew Yao discovered that Ruby's BigDecimal module did not properly allocate memory on 64-bit platforms. An attacker could use this flaw to cause a denial of service or possibly execute arbitrary code with user privileges. (CVE-2011-0188)
Nicholas Jefferson discovered that the FileUtils.remove_entry_secure method in Ruby did not properly remove non-empty directories. An attacker could use this flaw to possibly delete arbitrary files.
It was discovered that Ruby incorrectly allowed untainted strings to be modified in protective safe levels. An attacker could use this flaw to bypass intended access restrictions. (CVE-2011-1005)
Eric Wong discovered that Ruby does not properly reseed its pseudorandom number generator when creating child processes. An attacker could use this flaw to gain knowledge of the random numbers used in other Ruby child processes. (CVE-2011-2686)
Eric Wong discovered that the SecureRandom module in Ruby did not properly seed its pseudorandom number generator. An attacker could use this flaw to gain knowledge of the random numbers used by another Ruby process with the same process ID number. (CVE-2011-2705)
Alexander Klink and Julian Walde discovered that Ruby computed hash values without restricting the ability to trigger hash collisions predictably. A remote attacker could cause a denial of service by crafting values used in hash tables. (CVE-2011-4815).
Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
SolutionUpdate the affected libruby1.8 and / or ruby1.8 packages.