A flaw was found in the bash functionality that evaluates specially formatted environment variables passed to it from another environment. An attacker could use this feature to override or bypass restrictions to the environment to execute shell commands before restrictions have been applied. Certain services and applications allow remote unauthenticated attackers to provide environment variables, allowing them to exploit this issue.
Acknowledgements:
Red Hat would like to thank Stephane Chazelas for reporting this issue.
GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed function definitions in the values of environment variables, which allows remote attackers to write to files or possibly have unknown other impact via a crafted environment, as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the modcgi and modcgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution. NOTE: this vulnerability exists because of an incomplete fix for CVE-2014-6271.
Hyper-Threading technology, as used in FreeBSD and other operating systems that are run on Intel Pentium and other processors, allows local users to use a malicious thread to create covert channels, monitor the execution of other threads, and obtain sensitive information such as cryptographic keys, via a timing attack on memory cache misses.
The Internet Group Management Protocol (IGMP) allows local users to cause a denial of service via an IGMP membership report to a target's Ethernet address instead of the Multicast group address, which causes the target to stop sending reports to the router and effectively disconnect the group from the network.
cpio on FreeBSD 2.1.0, Debian GNU/Linux 3.0, and possibly other operating systems, uses a 0 umask when creating files using the -O (archive) or -F options, which creates the files with mode 0666 and allows local users to read or overwrite those files.
DISPUTED Kernel Samepage Merging (KSM) in the Linux kernel 2.6.32 through 4.x does not prevent use of a write-timing side channel, which allows guest OS users to defeat the ASLR protection mechanism on other guest OS instances via a Cross-VM ASL INtrospection (CAIN) attack. NOTE: the vendor states "Basically if you care about this attack vector, disable deduplication." Share-until-written approaches for memory conservation among mutually untrusting tenants are inherently detectable for information disclosure, and can be classified as potentially misunderstood behaviors rather than vulnerabilities.
pamldap in nssldap on Red Hat Enterprise Linux 4, Fedora Core 3 and earlier, and possibly other distributions does not return an error condition when an LDAP directory server responds with a PasswordPolicyResponse control response, which causes the pamauthenticate function to return a success code even if authentication has failed, as originally reported for xscreensaver.
A "stack overwrite" vulnerability in GnuPG (gpg) 1.x before 1.4.6, 2.x before 2.0.2, and 1.9.0 through 1.9.95 allows attackers to execute arbitrary code via crafted OpenPGP packets that cause GnuPG to dereference a function pointer from deallocated stack memory.
Integer signedness error in the CIFSFindNext function in fs/cifs/cifssmb.c in the Linux kernel before 3.1 allows remote CIFS servers to cause a denial of service (memory corruption) or possibly have unspecified other impact via a large length value in a response to a read request for a directory.
Dan Kaminsky pointed out that using partial MD4 and using that to generate a sequence number, of which only 24-bits are truly unguessable, seriously undermine the goals of random sequence number generation.
In particular, with only 24-bits being truly unguessable, packet injection into a session using even something like brute force is a real potential possibility.
We only use 24-bits because we regenerate the random number every 5 minutes "just in case." But what does is trade a "we don't know" kind of theoretical issue for a provably real one (brute force attack).
Therefore [Dave Miller] moving us more in line with RFC1948 (as well as OpenBSD and Solaris), to use MD5 and a full 32-bit result in the generated sequence number.
MD5 was selected as a compromise between performance loss and theoretical ability to be compromised. Willy Tarreau did extensive testing and SHA1 was found to harm performance too much to be considered seriously at this time.
We may later add a sysctl for various modes (ie. a "super secure" mode that uses SHA1 if people want that, and an "insecure" mode that doesn't use cryptographic hashing at all for people in protected environments where that might be safe to do).
[Dave Miller] also moved the sequence number generators out of random.c (they never really belonged there, and are only there due to historical artifacts), and fixed a bug in DCCP sequence number generation (on ipv6 the 43-bit sequence number was truncated to 32-bits).
Acknowledgements:
Red Hat would like to thank Dan Kaminsky for reporting this issue.
Currently, we skip doing the ispathaccessible check in cifsmount if there is no prefixpath. There is a report of at least one server however that allows a TREECONNECT to a share that has a DFS referral at its root. UNC that had no prefixpath was used in that case, so the ispathaccessible check was not triggered and the box later hit a BUG() because we were chasing a DFS referral on the root dentry for the mount. Upstream fix: 70945643722ffeac779d2529a348f99567fa5c33
References: https://bugzilla.redhat.com/showbug.cgi?id=682829 https://github.com/torvalds/linux/commit/70945643722ffeac779d2529a348f99567fa5c33
Acknowledgements:
Red Hat would like to thank Yogesh Sharma for reporting this issue.
http://kerneltrap.org/mailarchive/linux-netdev/2010/3/3/6271093/thread "The root cause for this problem is, when the receiver is doing releasesock() (i.e. after userspace recv, kernel udprecvmsg->skbfreedatagramlocked->releasesock), it moves skbs from backlog to skreceivequeue with the softirq enabled. In the above case, multiple busy senders will almost make it an endless loop. The skbs in the backlog end up eat all the system memory.
The issue is not only for UDP. Any protocols using socket backlog is potentially affected. The patch adds limit for socket backlog so that the backlog size cannot be expanded endlessly."
Upstream commits: http://git.kernel.org/linus/2499849ee8f513e795b9f2c19a42d6356e4943a4 http://git.kernel.org/linus/53eecb1be5ae499d399d2923933937a9ea1a284f http://git.kernel.org/linus/50b1a782f845140f4138f14a1ce8a4a6dd0cc82f http://git.kernel.org/linus/79545b681961d7001c1f4c3eb9ffb87bed4485db http://git.kernel.org/linus/55349790d7cbf0d381873a7ece1dcafcffd4aaa9 http://git.kernel.org/linus/6b03a53a5ab7ccf2d5d69f96cf1c739c4d2a8fb9 http://git.kernel.org/linus/8eae939f1400326b06d0c9afe53d2a484a326871 http://git.kernel.org/linus/a3a858ff18a72a8d388e31ab0d98f7e944841a62 http://git.kernel.org/linus/c377411f2494a931ff7facdbb3a6839b1266bcf6
Last updated 24 July 2024
Last updated 24 July 2024
IPv6 fragment identification generation is way beyond what we use for IPv4 : It uses a single generator. Its not scalable and allows DOS attacks.
Now inetpeer is IPv6 aware, we can use it to provide a more secure and scalable frag ident generator (per destination, instead of system wide)
This patch : 1) defines a new secureipv6id() helper 2) extends inetgetid() to provide 32bit results 3) extends ipv6selectident() with a new dest parameter
http://thread.gmane.org/gmane.linux.network/201773
Acknowledgements:
Red Hat would like to thank Fernando Gont for reporting this issue.
Last updated 24 July 2024
Race condition in the (1) loadelflibrary and (2) binfmtaout function calls for uselib in Linux kernel 2.4 through 2.429-rc2 and 2.6 through 2.6.10 allows local users to execute arbitrary code by manipulating the VMA descriptor.
Multiple drivers in Linux kernel 2.4.19 and earlier do not properly mark memory with the VMIO flag, which causes incorrect reference counts and may lead to a denial of service (kernel panic) when accessing freed kernel pages.
Xpdf, as used in products such as gpdf, kpdf, pdftohtml, poppler, teTeX, CUPS, libextractor, and others, allows attackers to cause a denial of service (infinite loop) via streams that end prematurely, as demonstrated using the (1) CCITTFaxDecode and (2) DCTDecode streams, aka "Infinite CPU spins."
Xpdf, as used in products such as gpdf, kpdf, pdftohtml, poppler, teTeX, CUPS, libextractor, and others, allows attackers to cause a denial of service (crash) via a crafted FlateDecode stream that triggers a null dereference.
udev does not properly set permissions on certain files in /dev/input, which allows local users to obtain sensitive data that is entered at the console, such as user passwords.
The CCITTFaxStream::CCITTFaxStream function in Stream.cc for xpdf, gpdf, kpdf, pdftohtml, poppler, teTeX, CUPS, libextractor, and others allows attackers to corrupt the heap via negative or large integers in a CCITTFaxDecode stream, which lead to integer overflows and integer underflows.
initscripts in Red Hat Enterprise Linux 4 does not properly handle certain environment variables when /sbin/service is executed, which allows local users with sudo permissions for /sbin/service to gain root privileges via unknown vectors.
The rawsendmsg function in the Linux kernel 2.6 before 2.6.13.1 allows local users to cause a denial of service (change hardware state) or read from arbitrary memory via crafted input.
The rwvm function in usercopy.c in the 4GB split patch for the Linux kernel in Red Hat Enterprise Linux 4 does not perform proper bounds checking, which allows local users to cause a denial of service (crash).
sysreport 1.3.15 and earlier includes contents of the up2date file in a report, which leaks the password for a proxy server in plaintext and allows local users to gain privileges.
Stack-based buffer overflow in the ieeeputascii function for nasm 0.98 and earlier allows attackers to execute arbitrary code via a crafted asm file, a different vulnerability than CVE-2004-1287.
Race condition in gzip 1.2.4, 1.3.3, and earlier, when decompressing a gzipped file, allows local users to modify permissions of arbitrary files via a hard link attack on a file while it is being decompressed, whose permissions are changed by gzip after the decompression is complete.
crontab in Vixie cron 4.1, when running with the -e option, allows local users to read the cron files of other users by changing the file being edited to a symlink. NOTE: there is insufficient information to know whether this is a duplicate of CVE-2001-0235.
scan.c for LibXPM may allow attackers to execute arbitrary code via a negative bitmapunit value that leads to a buffer overflow.