Citrix XenServer Multiple Vulnerabilities (CTX212736)
Critical Nessus Plugin ID 91352
SynopsisThe remote host is affected by multiple vulnerabilities.
DescriptionThe version of Citrix XenServer running on the remote host is affected by multiple vulnerabilities in the bundled versions of OpenSSL and QEMU :
- Multiple flaws exist in the bundled version of OpenSSL in the aesni_cbc_hmac_sha1_cipher() and aesni_cbc_hmac_sha256_cipher() functions that are triggered when the connection uses an AES-CBC cipher and AES-NI is supported by the server. A man-in-the-middle attacker can exploit these issues to conduct a padding oracle attack, resulting in the ability to decrypt the network traffic. (CVE-2016-2107)
- A remote code execution vulnerability exists in the bundled version of OpenSSL in the ASN.1 encoder component due to an underflow condition that occurs when attempting to encode the value zero represented as a negative integer. An unauthenticated, remote attacker can exploit this to corrupt memory, resulting in the execution of arbitrary code. (CVE-2016-2108)
- An out-of-bounds write error exists in the bundled version of QEMU in the vga_update_memory_access() function that is triggered when access nodes are changed after the register bank has been set. An attacker on the guest can exploit this to execute arbitrary code with the privileges of the host's QEMU process.
- An integer overflow condition exists in the bundled version of QEMU in the vbe_update_vgaregs() function that is triggered when setting certain VGA registers while in VBE mode. An attacker on the guest can exploit this to crash the host's QEMU process.
SolutionApply the appropriate hotfix as referenced in the vendor advisory.