SynopsisA video conferencing application running on the remote host is affected by multiple vulnerabilities.
DescriptionAccording to its self-reported version, the Cisco TelePresence Video Communication Server (VCS) / Expressway running on the remote host is 8.x prior to 8.8. It is, therefore, affected by multiple vulnerabilities :
- A security feature bypass vulnerability exists, known as Bar Mitzvah, due to improper combination of state data with key data by the RC4 cipher algorithm during the initialization phase. A man-in-the-middle attacker can exploit this, via a brute-force attack using LSB values, to decrypt the traffic. (CVE-2015-2808)
- A flaw exists in the web framework of TelePresence Video Communication Server (VCS) Expressway due to missing authorization checks on certain administrative pages. An authenticated, remote attacker can exploit this to bypass read-only restrictions and install Tandberg Linux Packages (TLPs) without proper authorization.
- A flaw exists in certificate management and validation for the Mobile and Remote Access (MRA) component due to improper input validation of a trusted certificate. An unauthenticated, remote attacker can exploit this, using a trusted certificate, to bypass authentication and gain access to internal HTTP system resources.
- A heap buffer overflow condition exists in the EVP_EncodeUpdate() function within file crypto/evp/encode.c that is triggered when handling a large amount of input data. An unauthenticated, remote attacker can exploit this to cause a denial of service condition. (CVE-2016-2105)
- A heap buffer overflow condition exists in the EVP_EncryptUpdate() function within file crypto/evp/evp_enc.c that is triggered when handling a large amount of input data after a previous call occurs to the same function with a partial block. An unauthenticated, remote attacker can exploit this to cause a denial of service condition. (CVE-2016-2106)
- Multiple flaws exist in the aesni_cbc_hmac_sha1_cipher() function in file crypto/evp/e_aes_cbc_hmac_sha1.c and the aesni_cbc_hmac_sha256_cipher() function in file crypto/evp/e_aes_cbc_hmac_sha256.c 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 to conduct a padding oracle attack, resulting in the ability to decrypt the network traffic.
- A remote code execution vulnerability exists in the ASN.1 encoder 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)
- Multiple unspecified flaws exist in the d2i BIO functions when reading ASN.1 data from a BIO due to invalid encoding causing a large allocation of memory.
An unauthenticated, remote attacker can exploit these to cause a denial of service condition through resource exhaustion. (CVE-2016-2109)
- An out-of-bounds read error exists in the X509_NAME_oneline() function within file crypto/x509/x509_obj.c when handling very long ASN.1 strings. An unauthenticated, remote attacker can exploit this to disclose the contents of stack memory.
- An information disclosure vulnerability exists in the file system permissions due to certain files having overly permissive permissions. An unauthenticated, local attacker can exploit this to disclose sensitive information. (Cisco bug ID CSCuw55636)
Note that Cisco bug ID CSCuw55636 and CVE-2015-6413 only affect versions 8.6.x prior to 8.8.
SolutionUpgrade to Cisco TelePresence VCS / Expressway version 8.8 or later.