Dear Linux Developers,
We're reaching out to you as part of the disclosure process of our research.
In our research, which we will present at IEEE Security & Privacy in May 2024, we found that attackers can not only create TCP-spoofed connections (which was already known), but can also reliably transmit IP-spoofed data over such connections. This has security implications for applications that rely on TCP endpoint IP addresses, such as firewalling or host-based authentication (e.g., SMTP/SPF, of DBs).
We basically discovered two TCP spoofing primitives. First, attackers can bruteforce the server-chosen send window by acknowledging data that was never sent (what we call "ghost ACKs"; see Figure 3 in the paper). Second, we show that there are side channels that allow the attacker to leak the otherwise-secret server-chosen initial sequence number (ISN). One of these side channels leverages TCP SYN cookies.
We believe that the TCP/IP stack can take countermeasures to prevent such attacks, or at least make them harder. For example, we think that TCP endpoints should ignore ghost ACKs, and have some ideas to randomize the TCP backlog queue to prevent the SYN cookie side channel.
At the same time, we have disclosed our findings to the IETF folks and hope that they have helpful feedback for us.
inftrees.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact by leveraging improper pointer arithmetic
An old inffast.c optimization turns out to not be optimal anymore with modern compilers, and furthermore was not compliant with the C standard, for which decrementing a pointer before its allocated memory is undefined.
External References:
https://wiki.mozilla.org/images/0/09/Zlib-report.pdf https://docs.google.com/document/d/10i1KZS5so8xDqH2rplRa2xet0tyTvvJlLbQQmZIUIKE/edit#heading=h.t13tvnx4loq7
Upstream patch:
https://github.com/madler/zlib/commit/9aaec95e82117c1cb0f9624264c3618fc380cecb
CVE assignment:
http://seclists.org/oss-sec/2016/q4/602
Last updated 13 November 2024
Last updated 31 October 2024
In BIG-IP versions 17.0.x before 17.0.0.1, 16.1.x before 16.1.3.1, 15.1.x before 15.1.7, 14.1.x before 14.1.5.1, and all versions of 13.1.x, and BIG-IQ all versions of 8.x and 7.x, an authenticated iControl REST user can cause an increase in memory resource utilization, via undisclosed requests.
Last updated 25 August 2025
Heap-based buffer overflow in the pack function in Perl before 5.26.2 allows context-dependent attackers to execute arbitrary code via a large item count.
A fundamental design flaw within the RADIUS protocol has been proven to be exploitable, compromising the integrity in the RADIUS Access-Request process. The attack allows a malicious user to modify packets in a way that would be indistinguishable to a RADIUS client or server. To be successful, the attacker must have the ability to inject themselves between the client and server.
In the Linux kernel, the following vulnerability has been resolved: tcp: do not accept ACK of bytes we never sent This patch is based on a detailed report and ideas from Yepeng Pan and Christian Rossow. ACK seq validation is currently following RFC 5961 5.2 guidelines: The ACK value is considered acceptable only if it is in the range of ((SND.UNA - MAX.SND.WND) <= SEG.ACK <= SND.NXT). All incoming segments whose ACK value doesn't satisfy the above condition MUST be discarded and an ACK sent back. It needs to be noted that RFC 793 on page 72 (fifth check) says: "If the ACK is a duplicate (SEG.ACK < SND.UNA), it can be ignored. If the ACK acknowledges something not yet sent (SEG.ACK > SND.NXT) then send an ACK, drop the segment, and return". The "ignored" above implies that the processing of the incoming data segment continues, which means the ACK value is treated as acceptable. This mitigation makes the ACK check more stringent since any ACK < SND.UNA wouldn't be accepted, instead only ACKs that are in the range ((SND.UNA - MAX.SND.WND) <= SEG.ACK <= SND.NXT) get through. This can be refined for new (and possibly spoofed) flows, by not accepting ACK for bytes that were never sent. This greatly improves TCP security at a little cost. I added a Fixes: tag to make sure this patch will reach stable trees, even if the 'blamed' patch was adhering to the RFC. tp->bytesacked was added in linux-4.2 Following packetdrill test (courtesy of Yepeng Pan) shows the issue at hand: 0 socket(..., SOCKSTREAM, IPPROTOTCP) = 3 +0 setsockopt(3, SOLSOCKET, SOREUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1024) = 0 // ---------------- Handshake ------------------- // // when window scale is set to 14 the window size can be extended to // 65535 (2^14) = 1073725440. Linux would accept an ACK packet // with ack number in (ServerISN+1-1073725440. ServerISN+1) // ,though this ack number acknowledges some data never // sent by the server. +0 < S 0:0(0) win 65535 +0 > S. 0:0(0) ack 1 <...> +0 < . 1:1(0) ack 1 win 65535 +0 accept(3, ..., ...) = 4 // For the established connection, we send an ACK packet, // the ack packet uses ack number 1 - 1073725300 + 2^32, // where 2^32 is used to wrap around. // Note: we used 1073725300 instead of 1073725440 to avoid possible // edge cases. // 1 - 1073725300 + 2^32 = 3221241997 // Oops, old kernels happily accept this packet. +0 < . 1:1001(1000) ack 3221241997 win 65535 // After the kernel fix the following will be replaced by a challenge ACK, // and prior malicious frame would be dropped. +0 > . 1:1(0) ack 1001
CVE-2019-3858 An out of bounds read flaw was discovered in libssh2 before 1.8.1 when a specially crafted SFTP packet is received from the server. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory. CVE-2019-3862 An out of bounds read flaw was discovered in libssh2 before 1.8.1 in the way SSHMSGCHANNELREQUEST packets with an exit status message and no payload are parsed. A remote attacker who compromises a SSH server may be able to cause a Denial of Service or read data in the client memory.
A server could send a specially crafted SSHMSGCHANNELREQUEST packet with an exit status message and no payload. This would result in an out of bounds memory comparison.
A server could send a specially crafted partial SFTP packet with a zero value for the payload length. This zero value would be used to then allocate memory resulting in a zero byte allocation and possible out of bounds read.
CVE-2016-10350 The archivereadformatcabreadheader function in archivereadsupportformatcab.c in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file. CVE-2016-10349 The archivele32dec function in archiveendian.h in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file.
CVE-2016-10350 The archivereadformatcabreadheader function in archivereadsupportformatcab.c in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file. CVE-2016-10349 The archivele32dec function in archiveendian.h in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file.
CVE-2016-10350 The archivereadformatcabreadheader function in archivereadsupportformatcab.c in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file. CVE-2016-10349 The archivele32dec function in archiveendian.h in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file.
CVE-2016-10350 The archivereadformatcabreadheader function in archivereadsupportformatcab.c in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file. CVE-2016-10349 The archivele32dec function in archiveendian.h in libarchive 3.2.2 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted file.
Last updated 7 May 2025
There is a MEDIUM severity vulnerability affecting CPython. Regular expressions that allowed excessive backtracking during tarfile. TarFile header parsing are vulnerable to ReDoS via specifically-crafted tar archives.
An authenticated attacker granted a Viewer or Auditor role on a BIG-IQ can upload arbitrary files using an undisclosed iControl REST endpoint. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
A use-after-free vulnerability was found in libarchive in RAR decoder. A crafted archive could cause the application to crash.
Upstream issue:
https://github.com/libarchive/libarchive/pull/1105
Upstream patch:
https://github.com/libarchive/libarchive/commit/bfcfe6f04ed20db2504db8a254d1f40a1d84eb28
A double free vulnerability was found in libarchive in RAR decoder. A crafted archive could cause the application to crash.
Upstream issue:
https://github.com/libarchive/libarchive/pull/1105
Upstream patch:
https://github.com/libarchive/libarchive/pull/1105/commits/021efa522ad729ff0f5806c4ce53e4a6cc1daa31
NET-SNMP version 5.7.2 contains a heap corruption vulnerability in the UDP protocol handler that can result in command execution.
setkey in agent/helpers/tablecontainer.c in Net-SNMP before 5.8 has a NULL Pointer Exception bug that can be used by an authenticated attacker to remotely cause the instance to crash via a crafted UDP packet, resulting in Denial of Service.