Calling getnetbyaddr or getnetbyaddrr with a configured nsswitch.conf that specifies the library's DNS backend for networks and queries for a zero-valued network in the GNU C Library version 2.0 to version 2.42 can leak stack contents to the configured DNS resolver.

Calling wordexp with WRDEREUSE in conjunction with WRDEAPPEND in the GNU C Library version 2.0 to version 2.42 may cause the interface to return uninitialized memory in the wewordv member, which on subsequent calls to wordfree may abort the process.

The resolver in glibc 2.1.3 uses predictable IDs, which allows a local attacker to spoof DNS query results.

An integer overflow, leading to buffer overflow flaw was found in the way the implementation of strcoll() routine, used to compare two strings based on the current locale, of glibc, the GNU libc libraries, performed calculation of memory requirements / allocation, needed for storage of the strings. If an application linked against glibc was missing an application-level sanity checks for validity of strcoll() arguments and accepted untrusted input, an attacker could use this flaw to cause the particular application to crash or, potentially, execute arbitrary code with the privileges of the user running the application.

Upstream bug report (including reproducer): [1] http://sourceware.org/bugzilla/showbug.cgi?id=14547

It was found that glibc's utility, responsible for editing of system's mtab table, improperly sanitized user supplied mount point names containing certain special character. Local attacker could use this flaw to add arbitrary mount points (corrupt system's "/etc/mtab" file) or, potentially, set unauthorized mount options. Other attacks are also possible.

Issue severity note: ------------------- The /etc/mtab file handles mounted devices and is automatically updated by the mount command (more precisely by the dedicated "mount" tool for relevant filesystem). Unprivileged user to be able to run such a tool (and modify content of /etc/mtab), this tool needs to be suid root enabled. The dedicated "mount" tools, as shipped with Red Hat Enterprise Linux (mount.cifs, mount.fuse, fusermount, mount.nfs, mount.nfs4) does NOT allow unprivileged user to use them (without prior grant of additional privileges from the privileged user) for editing of system's /etc/mtab file, which mitigates impact of this flaw.

A security flaw was found in the way strcoll() interface of glibc, the GNU libc libraries, performed failsafe back to alloca() routine when malloc() function call failed previously (due to out of memory [OOM] condition for example). If an application linked against glibc was missing an application-level sanity checks for validity of strcoll() arguments and accepted untrusted input, an attacker could use this flaw to cause the particular application to crash or, potentially, execute arbitrary code with the privileges of the user running the application.

Upstream bug report (including the reproducer): [1] http://sourceware.org/bugzilla/showbug.cgi?id=14552#c0

Issue / part: 1) alloca() stack overflow from [1].

References: [2] http://www.openwall.com/lists/oss-security/2012/09/07/9 [3] http://www.openwall.com/lists/oss-security/2012/09/07/15 [4] http://www.openwall.com/lists/oss-security/2012/09/10/1 [5] http://www.openwall.com/lists/oss-security/2012/09/10/3 [6] http://www.openwall.com/lists/oss-security/2012/09/13/16

The Sun RPC functionality in multiple libc implementations does not provide a time-out mechanism when reading data from TCP connections, which allows remote attackers to cause a denial of service (hang).

It was reported that if a process that called glibc's svcrun() exceeded the limit of opened files for a longer period of time, that accept() in rendezvousrequest()/svcudprecv() would fail with the EMFILE error, which would lead to looping between poll(), accept(), and 'for' loops which would consume a lot of CPU time. This could lead to an unresponsive system that requires human intervention (service restart or system restart) to resolve.

Common Vulnerabilities and Exposures assigned an identifier CVE-2009-4880 to the following vulnerability:

Multiple integer overflows in the strfmon implementation in the GNU C Library (aka glibc or libc6) 2.10.1 and earlier allow context-dependent attackers to cause a denial of service (memory consumption or application crash) via a crafted format string, as demonstrated by a crafted first argument to the moneyformat function in PHP, a related issue to CVE-2008-1391.

References: [1] http://securityreason.com/achievementsecurityalert/67 [2] https://bugzilla.redhat.com/showbug.cgi?id=524671 [3] http://sources.redhat.com/bugzilla/showbug.cgi?id=10600 [4] http://sourceware.org/git/?p=glibc.git;a=commit;h=199eb0de8d673fb23aa127721054b4f1803d61f3 [5] http://www.ubuntu.com/usn/USN-944-1 [6] http://www.securityfocus.com/bid/36443 [7] http://secunia.com/advisories/39900 [8] http://www.vupen.com/english/advisories/2010/1246

Public PoC (from [3]):

[cx@localhost ~]$ php -r 'moneyformat("%.1073741821i",1);' Segmentation fault

Common Vulnerabilities and Exposures assigned an identifier CVE-2009-4881 to the following vulnerability:

Integer overflow in the vstrfmonl function in stdlib/strfmonl.c in the strfmon implementation in the GNU C Library (aka glibc or libc6) before 2.10.1 allows context-dependent attackers to cause a denial of service (application crash) via a crafted format string, as demonstrated by the %99999999999999999999n string, a related issue to CVE-2008-1391.

References: [1] http://sources.redhat.com/bugzilla/showbug.cgi?id=10600 [2] http://sourceware.org/git/?p=glibc.git;a=commit;h=153aa31b93be22e01b236375fb02a9f9b9a0195f [3] http://sources.redhat.com/bugzilla/showbug.cgi?id=10600 [4] http://securityreason.com/achievementsecurityalert/53 [5] http://xorl.wordpress.com/2009/04/11/cve-2008-1391-netbsd-strfmon-integer-overflow/

Public PoC (from [4]):

#include <stdio.h> #include <monetary.h>

int main(int argc, char argv[]){ char buff[51]; char bux=buff; int res;

res=strfmon(bux, 50, argv[1], "0"); return 0; }

cxib# ./pln %99999999999999999999n

GNU glibc 2.3.4 before 2.3.4.20040619, 2.3.3 before 2.3.3.20040420, and 2.3.2 before 2.3.2-r10 does not restrict the use of LDDEBUG for a setuid program, which allows local users to gain sensitive information, such as the list of symbols used by the program.

The catchsegv script in glibc 2.3.2 and earlier allows local users to overwrite files via a symlink attack on temporary files.

The glibcbug script in glibc 2.3.4 and earlier allows local users to overwrite arbitrary files via a symlink attack on temporary files, a different vulnerability than CVE-2004-0968.