Certain Red Hat Enterprise Linux (RHEL) 4 and 5 packages for OpenSSH, as signed in August 2008 using a legitimate Red Hat GPG key, contain an externally introduced modification (Trojan Horse) that allows the package authors to have an unknown impact. NOTE: since the malicious packages were not distributed from any official Red Hat sources, the scope of this issue is restricted to users who may have obtained these packages through unofficial distribution points. As of 20080827, no unofficial distributions of this software are known.
OpenSSH before 5.1 sets the SO_REUSEADDR socket option when the X11UseLocalhost configuration setting is disabled, which allows local users on some platforms to hijack the X11 forwarding port via a bind to a single IP address, as demonstrated on the HP-UX platform.
sshd in OpenSSH 4 on Debian GNU/Linux, and the 20070303 OpenSSH snapshot, allows remote authenticated users to obtain access to arbitrary SELinux roles by appending a :/ (colon slash) sequence, followed by the role name, to the username.
OpenSSH 4.4 up to versions before 4.9 allows remote authenticated users to bypass the sshd_config ForceCommand directive by modifying the .ssh/rc session file.
OpenSSH 4.3p2, and probably other versions, allows local users to hijack forwarded X connections by causing ssh to set DISPLAY to :10, even when another process is listening on the associated port, as demonstrated by opening TCP port 6010 (IPv4) and sniffing a cookie sent by Emacs.
Stack-based buffer overflow in the command_Expand_Interpret function in command.c in ppp (aka user-ppp), as distributed in FreeBSD 6.3 and 7.0, OpenBSD 4.1 and 4.2, and the net/userppp package for NetBSD, allows local users to gain privileges via long commands containing "~" characters.
A certain pseudo-random number generator (PRNG) algorithm that uses XOR and 3-bit random hops (aka "Algorithm X3"), as used in OpenBSD 2.8 through 4.2, allows remote attackers to guess sensitive values such as DNS transaction IDs by observing a sequence of previously generated values. NOTE: this issue can be leveraged for attacks such as DNS cache poisoning against OpenBSD's modification of BIND.
A certain pseudo-random number generator (PRNG) algorithm that uses XOR and 2-bit random hops (aka "Algorithm X2"), as used in OpenBSD 2.6 through 3.4, Mac OS X 10 through 10.5.1, FreeBSD 4.4 through 7.0, and DragonFlyBSD 1.0 through 1.10.1, allows remote attackers to guess sensitive values such as IP fragmentation IDs by observing a sequence of previously generated values. NOTE: this issue can be leveraged for attacks such as injection into TCP packets and OS fingerprinting.
A certain pseudo-random number generator (PRNG) algorithm that uses ADD with 0 random hops (aka "Algorithm A0"), as used in OpenBSD 3.5 through 4.2 and NetBSD 1.6.2 through 4.0, allows remote attackers to guess sensitive values such as (1) DNS transaction IDs or (2) IP fragmentation IDs by observing a sequence of previously generated values. NOTE: this issue can be leveraged for attacks such as DNS cache poisoning, injection into TCP packets, and OS fingerprinting.
The ip6_check_rh0hdr function in netinet6/ip6_input.c in OpenBSD 4.2 allows attackers to cause a denial of service (panic) via malformed IPv6 routing headers.