Integer underflow in the cpuset_tasks_read function in the Linux kernel before 2.6.20.13, and 2.6.21.x before 2.6.21.4, when the cpuset filesystem is mounted, allows local users to obtain kernel memory contents by using a large offset when reading the /dev/cpuset/tasks file.

From Red Hat Security Advisory 2007:0705 :

Updated kernel packages that fix various security issues in the Red Hat Enterprise Linux 5 kernel are now available.

This update has been rated as having important security impact by the Red Hat Security Response Team.

The Linux kernel handles the basic functions of the operating system.

These new kernel packages contain fixes for the following security issues :

* a flaw in the DRM driver for Intel graphics cards that allowed a local user to access any part of the main memory. To access the DRM functionality a user must have access to the X server which is granted through the graphical login. This also only affected systems with an Intel 965 or later graphic chipset. (CVE-2007-3851, Important)

* a flaw in the VFAT compat ioctl handling on 64-bit systems that allowed a local user to corrupt a kernel_dirent struct and cause a denial of service (system crash). (CVE-2007-2878, Important)

* a flaw in the connection tracking support for SCTP that allowed a remote user to cause a denial of service by dereferencing a NULL pointer. (CVE-2007-2876, Important)

* flaw in the CIFS filesystem which could cause the umask values of a process to not be honored. This affected CIFS filesystems where the Unix extensions are supported. (CVE-2007-3740, Important)

* a flaw in the stack expansion when using the hugetlb kernel on PowerPC systems that allowed a local user to cause a denial of service. (CVE-2007-3739, Moderate)

* a flaw in the ISDN CAPI subsystem that allowed a remote user to cause a denial of service or potential remote access. Exploitation would require the attacker to be able to send arbitrary frames over the ISDN network to the victim's machine. (CVE-2007-1217, Moderate)

* a flaw in the cpuset support that allowed a local user to obtain sensitive information from kernel memory. To exploit this the cpuset filesystem would have to already be mounted. (CVE-2007-2875, Moderate)

* a flaw in the CIFS handling of the mount option 'sec=' that didn't enable integrity checking and didn't produce any error message.
(CVE-2007-3843, Low)

Red Hat Enterprise Linux 5 users are advised to upgrade to these packages, which contain backported patches to correct these issues.

Updated kernel packages that fix various security issues in the Red Hat Enterprise Linux 5 kernel are now available.

This update has been rated as having important security impact by the Red Hat Security Response Team.

The Linux kernel handles the basic functions of the operating system.

These new kernel packages contain fixes for the following security issues :

* a flaw in the DRM driver for Intel graphics cards that allowed a local user to access any part of the main memory. To access the DRM functionality a user must have access to the X server which is granted through the graphical login. This also only affected systems with an Intel 965 or later graphic chipset. (CVE-2007-3851, Important)

* a flaw in the VFAT compat ioctl handling on 64-bit systems that allowed a local user to corrupt a kernel_dirent struct and cause a denial of service (system crash). (CVE-2007-2878, Important)

* a flaw in the connection tracking support for SCTP that allowed a remote user to cause a denial of service by dereferencing a NULL pointer. (CVE-2007-2876, Important)

* flaw in the CIFS filesystem which could cause the umask values of a process to not be honored. This affected CIFS filesystems where the Unix extensions are supported. (CVE-2007-3740, Important)

* a flaw in the stack expansion when using the hugetlb kernel on PowerPC systems that allowed a local user to cause a denial of service. (CVE-2007-3739, Moderate)

* a flaw in the ISDN CAPI subsystem that allowed a remote user to cause a denial of service or potential remote access. Exploitation would require the attacker to be able to send arbitrary frames over the ISDN network to the victim's machine. (CVE-2007-1217, Moderate)

* a flaw in the cpuset support that allowed a local user to obtain sensitive information from kernel memory. To exploit this the cpuset filesystem would have to already be mounted. (CVE-2007-2875, Moderate)

* a flaw in the CIFS handling of the mount option 'sec=' that didn't enable integrity checking and didn't produce any error message.
(CVE-2007-3843, Low)

Red Hat Enterprise Linux 5 users are advised to upgrade to these packages, which contain backported patches to correct these issues.

A flaw was discovered in the PPP over Ethernet implementation. Local attackers could manipulate ioctls and cause kernel memory consumption leading to a denial of service. (CVE-2007-2525)

An integer underflow was discovered in the cpuset filesystem. If mounted, local attackers could obtain kernel memory using large file offsets while reading the tasks file. This could disclose sensitive data. (CVE-2007-2875)

Vilmos Nebehaj discovered that the SCTP netfilter code did not correctly validate certain states. A remote attacker could send a specially crafted packet causing a denial of service. (CVE-2007-2876)

Luca Tettamanti discovered a flaw in the VFAT compat ioctls on 64-bit systems. A local attacker could corrupt a kernel_dirent struct and cause a denial of service. (CVE-2007-2878)

A flaw in the sysfs_readdir function allowed a local user to cause a denial of service by dereferencing a NULL pointer. (CVE-2007-3104)

A buffer overflow was discovered in the random number generator. In environments with granular assignment of root privileges, a local attacker could gain additional privileges. (CVE-2007-3105)

A flaw was discovered in the usblcd driver. A local attacker could cause large amounts of kernel memory consumption, leading to a denial of service. (CVE-2007-3513)

Zhongling Wen discovered that the h323 conntrack handler did not correctly handle certain bitfields. A remote attacker could send a specially crafted packet and cause a denial of service.
(CVE-2007-3642)

A flaw was discovered in the CIFS mount security checking. Remote attackers could spoof CIFS network traffic, which could lead a client to trust the connection. (CVE-2007-3843)

It was discovered that certain setuid-root processes did not correctly reset process death signal handlers. A local user could manipulate this to send signals to processes they would not normally have access to. (CVE-2007-3848)

The Direct Rendering Manager for the i915 driver could be made to write to arbitrary memory locations. An attacker with access to a running X11 session could send a specially crafted buffer and gain root privileges. (CVE-2007-3851)

It was discovered that the aacraid SCSI driver did not correctly check permissions on certain ioctls. A local attacker could cause a denial of service or gain privileges. (CVE-2007-4308).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

A flaw was discovered in dvb ULE decapsulation. A remote attacker could send a specially crafted message and cause a denial of service.
(CVE-2006-4623)

The compat_sys_mount function allowed local users to cause a denial of service when mounting a smbfs filesystem in compatibility mode.
(CVE-2006-7203)

The Omnikey CardMan 4040 driver (cm4040_cs) did not limit the size of buffers passed to read() and write(). A local attacker could exploit this to execute arbitrary code with kernel privileges. (CVE-2007-0005)

Due to an variable handling flaw in the ipv6_getsockopt_sticky() function a local attacker could exploit the getsockopt() calls to read arbitrary kernel memory. This could disclose sensitive data.
(CVE-2007-1000)

Ilja van Sprundel discovered that Bluetooth setsockopt calls could leak kernel memory contents via an uninitialized stack buffer. A local attacker could exploit this flaw to view sensitive kernel information.
(CVE-2007-1353)

A flaw was discovered in the handling of netlink messages. Local attackers could cause infinite recursion leading to a denial of service. (CVE-2007-1861)

The random number generator was hashing a subset of the available entropy, leading to slightly less random numbers. Additionally, systems without an entropy source would be seeded with the same inputs at boot time, leading to a repeatable series of random numbers.
(CVE-2007-2453)

A flaw was discovered in the PPP over Ethernet implementation. Local attackers could manipulate ioctls and cause kernel memory consumption leading to a denial of service. (CVE-2007-2525)

An integer underflow was discovered in the cpuset filesystem. If mounted, local attackers could obtain kernel memory using large file offsets while reading the tasks file. This could disclose sensitive data. (CVE-2007-2875)

Vilmos Nebehaj discovered that the SCTP netfilter code did not correctly validate certain states. A remote attacker could send a specially crafted packet causing a denial of service. (CVE-2007-2876)

Luca Tettamanti discovered a flaw in the VFAT compat ioctls on 64-bit systems. A local attacker could corrupt a kernel_dirent struct and cause a denial of service. (CVE-2007-2878)

A flaw was discovered in the cluster manager. A remote attacker could connect to the DLM port and block further DLM operations.
(CVE-2007-3380)

A flaw was discovered in the usblcd driver. A local attacker could cause large amounts of kernel memory consumption, leading to a denial of service. (CVE-2007-3513).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The compat_sys_mount function allowed local users to cause a denial of service when mounting a smbfs filesystem in compatibility mode.
(CVE-2006-7203)

The Omnikey CardMan 4040 driver (cm4040_cs) did not limit the size of buffers passed to read() and write(). A local attacker could exploit this to execute arbitrary code with kernel privileges. (CVE-2007-0005)

Due to a variable handling flaw in the ipv6_getsockopt_sticky() function a local attacker could exploit the getsockopt() calls to read arbitrary kernel memory. This could disclose sensitive data.
(CVE-2007-1000)

Ilja van Sprundel discovered that Bluetooth setsockopt calls could leak kernel memory contents via an uninitialized stack buffer. A local attacker could exploit this flaw to view sensitive kernel information.
(CVE-2007-1353)

A flaw was discovered in the handling of netlink messages. Local attackers could cause infinite recursion leading to a denial of service. (CVE-2007-1861)

A flaw was discovered in the IPv6 stack's handling of type 0 route headers. By sending a specially crafted IPv6 packet, a remote attacker could cause a denial of service between two IPv6 hosts.
(CVE-2007-2242)

The random number generator was hashing a subset of the available entropy, leading to slightly less random numbers. Additionally, systems without an entropy source would be seeded with the same inputs at boot time, leading to a repeatable series of random numbers.
(CVE-2007-2453)

A flaw was discovered in the PPP over Ethernet implementation. Local attackers could manipulate ioctls and cause kernel memory consumption leading to a denial of service. (CVE-2007-2525)

An integer underflow was discovered in the cpuset filesystem. If mounted, local attackers could obtain kernel memory using large file offsets while reading the tasks file. This could disclose sensitive data. (CVE-2007-2875)

Vilmos Nebehaj discovered that the SCTP netfilter code did not correctly validate certain states. A remote attacker could send a specially crafted packet causing a denial of service. (CVE-2007-2876)

Luca Tettamanti discovered a flaw in the VFAT compat ioctls on 64-bit systems. A local attacker could corrupt a kernel_dirent struct and cause a denial of service. (CVE-2007-2878).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Some vulnerabilities were discovered and corrected in the Linux 2.6 kernel :

The Linux kernel did not properly save or restore EFLAGS during a context switch, or reset the flags when creating new threads, which allowed local users to cause a denial of service (process crash) (CVE-2006-5755).

The compat_sys_mount function in fs/compat.c allowed local users to cause a denial of service (NULL pointer dereference and oops) by mounting a smbfs file system in compatibility mode (CVE-2006-7203).

The nfnetlink_log function in netfilter allowed an attacker to cause a denial of service (crash) via unspecified vectors which would trigger a NULL pointer dereference (CVE-2007-1496).

The nf_conntrack function in netfilter did not set nfctinfo during reassembly of fragmented packets, which left the default value as IP_CT_ESTABLISHED and could allow remote attackers to bypass certain rulesets using IPv6 fragments (CVE-2007-1497).

The netlink functionality did not properly handle NETLINK_FIB_LOOKUP replies, which allowed a remote attacker to cause a denial of service (resource consumption) via unspecified vectors, probably related to infinite recursion (CVE-2007-1861).

A typo in the Linux kernel caused RTA_MAX to be used as an array size instead of RTN_MAX, which lead to an out of bounds access by certain functions (CVE-2007-2172).

The IPv6 protocol allowed remote attackers to cause a denial of service via crafted IPv6 type 0 route headers that create network amplification between two routers (CVE-2007-2242).

The random number feature did not properly seed pools when there was no entropy, or used an incorrect cast when extracting entropy, which could cause the random number generator to provide the same values after reboots on systems without an entropy source (CVE-2007-2453).

A memory leak in the PPPoE socket implementation allowed local users to cause a denial of service (memory consumption) by creating a socket using connect, and releasing it before the PPPIOCGCHAN ioctl is initialized (CVE-2007-2525).

An integer underflow in the cpuset_tasks_read function, when the cpuset filesystem is mounted, allowed local users to obtain kernel memory contents by using a large offset when reading the /dev/cpuset/tasks file (CVE-2007-2875).

The sctp_new function in netfilter allowed remote attackers to cause a denial of service by causing certain invalid states that triggered a NULL pointer dereference (CVE-2007-2876).

In addition to these security fixes, other fixes have been included such as :

  - Fix crash on netfilter when nfnetlink_log is used on     certain hooks on packets forwarded to or from a bridge

  - Fixed busy sleep on IPVS which caused high load averages

    - Fixed possible race condition on ext[34]_link

    - Fixed missing braces in condition block that led to       wrong behaviour in NFS

  - Fixed XFS lock deallocation that resulted in oops when     unmounting

To update your kernel, please follow the directions located at :

http://www.mandriva.com/en/security/kernelupdate

Several local and remote vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or the execution of arbitrary code. The Common Vulnerabilities and Exposures project identifies the following problems :

  - CVE-2007-2172     Thomas Graf reported a typo in the IPv4 protocol handler     that could be used by a local attacker to overrun an     array via crafted packets, potentially resulting in a     Denial of Service (system crash). The DECnet counterpart     of this issue was already fixed in DSA-1356.

  - CVE-2007-2875     iDefense reported a potential integer underflow in the     cpuset filesystem which may permit local attackers to     gain access to sensitive kernel memory. This     vulnerability is only exploitable if the cpuset     filesystem is mounted.

  - CVE-2007-3105     The PaX Team discovered a potential buffer overflow in     the random number generator which may permit local users     to cause a denial of service or gain additional     privileges. This issue is not believed to effect default     Debian installations where only root has sufficient     privileges to exploit it.

  - CVE-2007-3843     A coding error in the CIFS subsystem permits the use of     unsigned messages even if the client has configured the     system to enforce signing by passing the sec=ntlmv2i     mount option. This may allow remote attackers to spoof     CIFS network traffic.

  - CVE-2007-4308     Alan Cox reported an issue in the aacraid driver that     allows unprivileged local users to make ioctl calls     which should be restricted to admin privileges.

These problems have been fixed in the stable distribution in version 2.6.18.dfsg.1-13etch2.

The following matrix lists additional packages that were rebuilt for compatibility with or to take advantage of this update :

                    Debian 4.0 (etch)    fai-kernels        1.17+etch5           user-mode-linux    2.6.18-1um-2etch4

The remote CentOS system is missing a security update which has been documented in Red Hat advisory RHSA-2007-0705.

ID	Name	Product	Family	Severity
67543	Oracle Linux 5 : kernel (ELSA-2007-0705)	Nessus	Oracle Linux Local Security Checks	medium
43648	CentOS 5 : kernel (CESA-2007:0705)	Nessus	CentOS Local Security Checks	medium
28114	Ubuntu 7.04 : linux-source-2.6.20 vulnerabilities (USN-510-1)	Nessus	Ubuntu Local Security Checks	high
28090	Ubuntu 6.06 LTS : linux-source-2.6.15 vulnerability (USN-489-1)	Nessus	Ubuntu Local Security Checks	high
28087	Ubuntu 6.10 : linux-source-2.6.17 vulnerabilities (USN-486-1)	Nessus	Ubuntu Local Security Checks	high
26050	RHEL 5 : kernel (RHSA-2007:0705)	Nessus	Red Hat Local Security Checks	medium
25968	Mandrake Linux Security Advisory : kernel (MDKSA-2007:171)	Nessus	Mandriva Local Security Checks	high
25963	Debian DSA-1363-1 : linux-2.6 - several vulnerabilities	Nessus	Debian Local Security Checks	medium
801434	CentOS RHSA-2007-0705 Security Check	Log Correlation Engine	Generic	high

Detections

Analytics

CVE-2007-2875

high

Tenable Plugins

medium

medium

high

high

high

medium

high

medium

high