In some cases, the `tcp-setmss` handler may free the packet data and throw an error without halting the rule processing engine. A subsequent rule can then allow the traffic after the packet data is gone, resulting in a NULL pointer dereference. Maliciously crafted packets sent from a remote host may result in a Denial of Service (DoS) if the `tcp-setmss` directive is used and a subsequent rule would allow the traffic to pass.
The do_change_cipher_spec function in OpenSSL 0.9.6c to 0.9.6k, and 0.9.7a to 0.9.7c, allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that triggers a null dereference.
On a system exposing an NVMe/TCP target, a remote client can trigger a kernel panic by sending a CONNECT command for an I/O queue with a bogus or stale CNTLID. An attacker with network access to the NVMe/TCP target can trigger an unauthenticated Denial of Service condition on the affected machine.
It was found in FreeBSD 8.0, 6.3 and 4.9, and OpenBSD 4.6 that a null pointer dereference in ftpd/popen.c may lead to remote denial of service of the ftpd service.
Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).
sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz, related to kex.c and packet.c.
In OpenBSD 7.4 before errata 006 and OpenBSD 7.3 before errata 020, httpd(8) is vulnerable to a NULL dereference when handling a malformed fastcgi request.
rwho daemon rwhod in FreeBSD 4.2 and earlier, and possibly other operating systems, allows remote attackers to cause a denial of service via malformed packets with a short length.
Memory leak in the OBJ_obj2txt function in LibreSSL before 2.3.1 allows remote attackers to cause a denial of service (memory consumption) via a large number of ASN.1 object identifiers in X.509 certificates.
The getnameinfo function in FreeBSD 4.1.1 and earlier, and possibly other operating systems, allows a remote attacker to cause a denial of service via a long DNS hostname.
A set of carefully crafted ipv6 packets can trigger an integer overflow in the calculation of a fragment reassembled packet's payload length field. This allows an attacker to trigger a kernel panic, resulting in a denial of service.
telnetd in FreeBSD 4.2 and earlier, and possibly other operating systems, allows remote attackers to cause a denial of service by specifying an arbitrary large file in the TERMCAP environmental variable, which consumes resources as the server processes the file.
In OpenBSD 7.2, a TCP packet with destination port 0 that matches a pf divert-to rule can crash the kernel.
FTP servers such as OpenBSD ftpd, NetBSD ftpd, ProFTPd and Opieftpd do not properly cleanse untrusted format strings that are used in the setproctitle function (sometimes called by set_proc_title), which allows remote attackers to cause a denial of service or execute arbitrary commands.
A certain Debian patch for OpenSSH before 4.3p2-9etch3 on etch; before 4.6p1-1 on sid and lenny; and on other distributions such as SUSE uses functions that are not async-signal-safe in the signal handler for login timeouts, which allows remote attackers to cause a denial of service (connection slot exhaustion) via multiple login attempts. NOTE: this issue exists because of an incorrect fix for CVE-2006-5051.
The IPSEC implementation in OpenBSD 2.7 does not properly handle empty AH/ESP packets, which allows remote attackers to cause a denial of service.
NetBSD 1.4.2 and earlier allows remote attackers to cause a denial of service by sending a packet with an unaligned IP timestamp option.
OpenBSD 2.6 and earlier allows remote attackers to cause a denial of service by flooding the server with ARP requests.
IP fragment assembly in OpenBSD 2.4 allows a remote attacker to cause a denial of service by sending a large number of fragmented packets.
In FreeBSD 13.0-STABLE before n245765-bec0d2c9c841, 12.2-STABLE before r369859, 11.4-STABLE before r369866, 13.0-RELEASE before p1, 12.2-RELEASE before p7, and 11.4-RELEASE before p10, missing message validation in libradius(3) could allow malicious clients or servers to trigger denial of service in vulnerable servers or clients respectively.
Operating systems with shared memory implementations based on BSD 4.4 code allow a user to conduct a denial of service and bypass memory limits (e.g., as specified with rlimits) using mmap or shmget to allocate memory and cause page faults.
Denial of service in WU-FTPD via the SITE NEWER command, which does not free memory properly.
The ipalloc function in libc/stdlib/malloc.c in jemalloc in libc for FreeBSD 6.4 and NetBSD does not properly allocate memory, which makes it easier for context-dependent attackers to perform memory-related attacks such as buffer overflows via a large size value, related to "integer rounding and overflow" errors.
FreeBSD allows local users to conduct a denial of service by creating a hard link from a device special file to a file on an NFS file system.
ICMP messages to broadcast addresses are allowed, allowing for a Smurf attack that can cause a denial of service.
ip_input.c in BSD-derived TCP/IP implementations allows remote attackers to cause a denial of service (crash or hang) via crafted packets.
Jolt ICMP attack causes a denial of service in Windows 95 and Windows NT systems.
One of the data structures that holds TCP segments in all versions of FreeBSD prior to 11.2-RELEASE-p1, 11.1-RELEASE-p12, and 10.4-RELEASE-p10 uses an inefficient algorithm to reassemble the data. This causes the CPU time spent on segment processing to grow linearly with the number of segments in the reassembly queue. An attacker who has the ability to send TCP traffic to a victim system can degrade the victim system's network performance and/or consume excessive CPU by exploiting the inefficiency of TCP reassembly handling, with relatively small bandwidth cost.
OpenBSD before 20070116 allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via certain IPv6 ICMP (aka ICMP6) echo request packets.
The libarchive library in FreeBSD 6-STABLE after 2006-09-05 and before 2006-11-08 allows context-dependent attackers to cause a denial of service (CPU consumption) via a malformed archive that causes libarchive to skip a region past the actual end of the archive, which triggers an infinite loop that attempts to read more data.
The ssh_packet_read_poll2 function in packet.c in OpenSSH before 7.1p2 allows remote attackers to cause a denial of service (out-of-bounds read and application crash) via crafted network traffic.
Incorrect packet validation allowed unbounded recursion parsing SCTP chunk parameters. This can eventually result in a stack overflow and panic. Remote attackers can craft packets which cause affected systems to panic. This affects any system where pf is configured to process traffic, independent of the configured ruleset.
Selective Acknowledgement (SACK) in FreeBSD 5.3 and 5.4 does not properly handle an incoming selective acknowledgement when there is insufficient memory, which might allow remote attackers to cause a denial of service (infinite loop).
The ipfw firewall in FreeBSD 6.0-RELEASE allows remote attackers to cause a denial of service (firewall crash) via ICMP IP fragments that match a reset, reject or unreach action, which leads to an access of an uninitialized pointer.
Multiple vulnerabilities in the SACK functionality in (1) tcp_input.c and (2) tcp_usrreq.c OpenBSD 3.5 and 3.6 allow remote attackers to cause a denial of service (memory exhaustion or system crash).
The TCP stack (tcp_input.c) in OpenBSD 3.5 and 3.6 allows remote attackers to cause a denial of service (system panic) via crafted values in the TCP timestamp option, which causes invalid arguments to be used when calculating the retransmit timeout.
Multiple TCP implementations with Protection Against Wrapped Sequence Numbers (PAWS) with the timestamps option enabled allow remote attackers to cause a denial of service (connection loss) via a spoofed packet with a large timer value, which causes the host to discard later packets because they appear to be too old.
sshd.c in OpenSSH 3.6.1p2 and 3.7.1p2 and possibly other versions, when using privilege separation, does not properly signal the non-privileged process when a session has been terminated after exceeding the LoginGraceTime setting, which leaves the connection open and allows remote attackers to cause a denial of service (connection consumption).
The bridge functionality in OpenBSD 3.4 and 3.5, when running a gateway configured as a bridging firewall with the link2 option for IPSec enabled, allows remote attackers to cause a denial of service (crash) via an ICMP echo (ping) packet.
Integer overflow in the "Max-dotdot" CVS protocol command (serve_max_dotdot) for CVS 1.12.x through 1.12.8, and 1.11.x through 1.11.16, may allow remote attackers to cause a server crash, which could cause temporary data to remain undeleted and consume disk space.
isakmpd in OpenBSD 3.4 and earlier allows remote attackers to cause a denial of service (crash) via an ISAKMP packet with a delete payload containing a large number of SPIs, which triggers an out-of-bounds read error, as demonstrated by the Striker ISAKMP Protocol Test Suite.
OpenSSL 0.9.6 before 0.9.6d does not properly handle unknown message types, which allows remote attackers to cause a denial of service (infinite loop), as demonstrated using the Codenomicon TLS Test Tool.
isakmpd in OpenBSD 3.4 and earlier allows remote attackers to cause a denial of service (crash) via an ISAKMP packet with a malformed IPSEC SA payload, as demonstrated by the Striker ISAKMP Protocol Test Suite.
Multiple memory leaks in isakmpd in OpenBSD 3.4 and earlier allow remote attackers to cause a denial of service (memory exhaustion) via certain ISAKMP packets, as demonstrated by the Striker ISAKMP Protocol Test Suite.
isakmpd in OpenBSD 3.4 and earlier allows remote attackers to cause a denial of service (infinite loop) via an ISAKMP packet with a zero-length payload, as demonstrated by the Striker ISAKMP Protocol Test Suite.
FreeBSD 5.1 and earlier, and Mac OS X before 10.3.4, allows remote attackers to cause a denial of service (resource exhaustion of memory buffers and system crash) via a large number of out-of-sequence TCP packets, which prevents the operating system from creating new connections.
The SSL/TLS handshaking code in OpenSSL 0.9.7a, 0.9.7b, and 0.9.7c, when using Kerberos ciphersuites, does not properly check the length of Kerberos tickets during a handshake, which allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that causes an out-of-bounds read.
When a challenge ACK is to be sent tcp_respond() constructs and sends the challenge ACK and consumes the mbuf that is passed in. When no challenge ACK should be sent the function returns and leaks the mbuf. If an attacker is either on path with an established TCP connection, or can themselves establish a TCP connection, to an affected FreeBSD machine, they can easily craft and send packets which meet the challenge ACK criteria and cause the FreeBSD host to leak an mbuf for each crafted packet in excess of the configured rate limit settings i.e. with default settings, crafted packets in excess of the first 5 sent within a 1s period will leak an mbuf. Technically, off-path attackers can also exploit this problem by guessing the IP addresses, TCP port numbers and in some cases the sequence numbers of established connections and spoofing packets towards a FreeBSD machine, but this is harder to do effectively.
BIND 8.x through 8.3.3 allows remote attackers to cause a denial of service (crash) via SIG RR elements with invalid expiry times, which are removed from the internal BIND database and later cause a null dereference.
BIND 8.3.x through 8.3.3 allows remote attackers to cause a denial of service (termination due to assertion failure) via a request for a subdomain that does not exist, with an OPT resource record with a large UDP payload size.