The mpipowm function in Libgcrypt before 1.6.3 and GnuPG before 1.4.19 allows attackers to obtain sensitive information by leveraging timing differences when accessing a pre-computed table during modular exponentiation, related to a "Last-Level Cache Side-Channel Attack."

Libgcrypt before 1.6.3 and GnuPG before 1.4.19 does not implement ciphertext blinding for Elgamal decryption, which allows physically proximate attackers to obtain the server's private key by determining factors using crafted ciphertext and the fluctuations in the electromagnetic field during multiplication.

DISPUTED In Libgcrypt 1.8.4, the C implementation of AES is vulnerable to a flush-and-reload side-channel attack because physical addresses are available to other processes. (The C implementation is used on platforms where an assembly-language implementation is unavailable.) NOTE: the vendor's position is that the issue report cannot be validated because there is no description of an attack.

DISPUTED cryptlib through 3.4.4 allows a memory-cache side-channel attack on DSA and ECDSA signatures, aka the Return Of the Hidden Number Problem or ROHNP. To discover a key, the attacker needs access to either the local machine or a different virtual machine on the same physical host. NOTE: the vendor does not include side-channel attacks within its threat model.

The mixing functions in the random number generator in Libgcrypt before 1.5.6, 1.6.x before 1.6.6, and 1.7.x before 1.7.3 and GnuPG before 1.4.21 make it easier for attackers to obtain the values of 160 bits by leveraging knowledge of the previous 4640 bits.

Libgcrypt before 1.6.5 does not properly perform elliptic-point curve multiplication during decryption, which makes it easier for physically proximate attackers to extract ECDH keys by measuring electromagnetic emanations.

Libgcrypt before 1.5.4, as used in GnuPG and other products, does not properly perform ciphertext normalization and ciphertext randomization, which makes it easier for physically proximate attackers to conduct key-extraction attacks by leveraging the ability to collect voltage data from exposed metal, a different vector than CVE-2013-4576.

GnuPG before 1.4.14, and Libgcrypt before 1.5.3 as used in GnuPG 2.0.x and possibly other products, allows local users to obtain private RSA keys via a cache side-channel attack involving the L3 cache, aka Flush+Reload.

Created attachment 629285 [details] patch to fix the buffer overflow

Description of problem: A buffer overflow in mcrypt version 2.6.8 and earlier due to long filenames. If a user were tricked into attempting to encrypt/decrypt specially crafted long filename(s), this flaw would cause a stack-based buffer overflow that could potentially lead to arbitrary code execution.

Note that this is caught by FORTIFYSOURCE, which renders this to being a crash-only bug on Fedora.

There are currently no upstream patches for this flaw.

Version-Release number of selected component (if applicable): mcrypt-2.6.8-9.el6 (possibly others too).

How reproducible: Run mcrypt with ~128 byte long file names.