Integer overflow in Linux kernel 2.6 allows local users to overwrite kernel memory by writing to a sysfs file.

Updated kernel packages that fix several security issues are now available for Red Hat Enterprise Linux 4.

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

[Updated 9 August 2005] The advisory text has been updated to show that this update fixed the security issue named CVE-2005-0210 but not CVE-2005-0209. The issue CVE-2005-0209 was actually fixed by RHSA-2005:420. No changes have been made to the packages associated with this advisory.

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

A flaw in the fib_seq_start function was discovered. A local user could use this flaw to cause a denial of service (system crash) via /proc/net/route. (CVE-2005-1041)

A flaw in the tmpfs file system was discovered. A local user could use this flaw to cause a denial of service (system crash). (CVE-2005-0977)

An integer overflow flaw was found when writing to a sysfs file. A local user could use this flaw to overwrite kernel memory, causing a denial of service (system crash) or arbitrary code execution.
(CVE-2005-0867)

Keith Owens reported a flaw in the Itanium unw_unwind_to_user function. A local user could use this flaw to cause a denial of service (system crash) on Itanium architectures. (CVE-2005-0135)

A flaw in the NFS client O_DIRECT error case handling was discovered.
A local user could use this flaw to cause a denial of service (system crash). (CVE-2005-0207)

A small memory leak when defragmenting local packets was discovered that affected the Linux 2.6 kernel netfilter subsystem. A local user could send a large number of carefully crafted fragments leading to memory exhaustion (CVE-2005-0210)

A flaw was discovered in the Linux PPP driver. On systems allowing remote users to connect to a server using ppp, a remote client could cause a denial of service (system crash). (CVE-2005-0384)

A flaw was discovered in the ext2 file system code. When a new directory is created, the ext2 block written to disk is not initialized, which could lead to an information leak if a disk image is made available to unprivileged users. (CVE-2005-0400)

A flaw in fragment queuing was discovered that affected the Linux kernel netfilter subsystem. On systems configured to filter or process network packets (e.g. firewalling), a remote attacker could send a carefully crafted set of fragmented packets to a machine and cause a denial of service (system crash). In order to sucessfully exploit this flaw, the attacker would need to know or guess some aspects of the firewall ruleset on the target system. (CVE-2005-0449)

A number of flaws were found in the Linux 2.6 kernel. A local user could use these flaws to read kernel memory or cause a denial of service (crash). (CVE-2005-0529, CVE-2005-0530, CVE-2005-0531)

An integer overflow in sys_epoll_wait in eventpoll.c was discovered. A local user could use this flaw to overwrite low kernel memory. This memory is usually unused, not usually resulting in a security consequence. (CVE-2005-0736)

A flaw when freeing a pointer in load_elf_library was discovered. A local user could potentially use this flaw to cause a denial of service (crash). (CVE-2005-0749)

A flaw was discovered in the bluetooth driver system. On systems where the bluetooth modules are loaded, a local user could use this flaw to gain elevated (root) privileges. (CVE-2005-0750)

A race condition was discovered that affected the Radeon DRI driver. A local user who has DRI privileges on a Radeon graphics card may be able to use this flaw to gain root privileges. (CVE-2005-0767)

Multiple range checking flaws were discovered in the iso9660 file system handler. An attacker could create a malicious file system image which would cause a denial or service or potentially execute arbitrary code if mounted. (CVE-2005-0815)

A flaw was discovered when setting line discipline on a serial tty. A local user may be able to use this flaw to inject mouse movements or keystrokes when another user is logged in. (CVE-2005-0839)

Red Hat Enterprise Linux 4 users are advised to upgrade their kernels to the packages associated with their machine architectures and configurations as listed in this erratum.

Please note that

Alexander Nyberg discovered an integer overflow in the sysfs_write_file() function. A local attacker could exploit this to crash the kernel or possibly even execute arbitrary code with root privileges by writing to an user-writable file in /sys under certain low-memory conditions. However, there are very few cases where a user-writeable sysfs file actually exists. (CAN-2005-0867)

Olof Johansson discovered a Denial of Service vulnerability in the futex functions, which provide semaphores for exclusive locking of resources. A local attacker could possibly exploit this to cause a kernel deadlock. (CAN-2005-0937)

In addition this update fixes two race conditions in the ext3 and jfs file system drivers, which could lead to a kernel crash under certain (unusual) conditions. However, these cannot easily be triggered by users, thus they are not security sensitive.
(http://linux.bkbits.net:8080/linux-2.5/gnupatch@4248d87aETPJX79hVXl4o wAUwu2SmQ, http://linux.bkbits.net:8080/linux-2.6/cset@1.2181.46.242)

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 remote Redhat Enterprise Linux 4 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2005:366 advisory.

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

    A flaw in the fib_seq_start function was discovered. A local user could use     this flaw to cause a denial of service (system crash) via /proc/net/route.
    (CAN-2005-1041)

    A flaw in the tmpfs file system was discovered. A local user could use this     flaw to cause a denial of service (system crash). (CAN-2005-0977)

    An integer overflow flaw was found when writing to a sysfs file. A local     user could use this flaw to overwrite kernel memory, causing a denial of     service (system crash) or arbitrary code execution. (CAN-2005-0867)

    Keith Owens reported a flaw in the Itanium unw_unwind_to_user function. A     local user could use this flaw to cause a denial of service (system crash)     on Itanium architectures. (CAN-2005-0135)

    A flaw in the NFS client O_DIRECT error case handling was discovered. A     local user could use this flaw to cause a denial of service (system crash).
    (CAN-2005-0207)

    A small memory leak when defragmenting local packets was discovered that     affected the Linux 2.6 kernel netfilter subsystem.  A local user could send     a large number of carefully crafted fragments leading to memory exhaustion     (CAN-2005-0210)

    A flaw was discovered in the Linux PPP driver. On systems allowing remote     users to connect to a server using ppp, a remote client could cause a     denial of service (system crash). (CAN-2005-0384)

    A flaw was discovered in the ext2 file system code. When a new directory is     created, the ext2 block written to disk is not initialized, which could     lead to an information leak if a disk image is made available to     unprivileged users. (CAN-2005-0400)

    A flaw in fragment queuing was discovered that affected the Linux kernel     netfilter subsystem. On systems configured to filter or process network     packets (e.g. firewalling), a remote attacker could send a carefully     crafted set of fragmented packets to a machine and cause a denial of     service (system crash). In order to sucessfully exploit this flaw, the     attacker would need to know or guess some aspects of the firewall ruleset     on the target system. (CAN-2005-0449)

    A number of flaws were found in the Linux 2.6 kernel. A local user could     use these flaws to read kernel memory or cause a denial of service (crash).
    (CAN-2005-0529, CAN-2005-0530, CAN-2005-0531)

    An integer overflow in sys_epoll_wait in eventpoll.c was discovered. A     local user could use this flaw to overwrite low kernel memory. This memory     is usually unused, not usually resulting in a security consequence.
    (CAN-2005-0736)

    A flaw when freeing a pointer in load_elf_library was discovered. A local     user could potentially use this flaw to cause a denial of service (crash).
    (CAN-2005-0749)

    A flaw was discovered in the bluetooth driver system. On systems where the     bluetooth modules are loaded, a local user could use this flaw to gain     elevated (root) privileges. (CAN-2005-0750)

    A race condition was discovered that affected the Radeon DRI driver. A     local user who has DRI privileges on a Radeon graphics card may be able to     use this flaw to gain root privileges. (CAN-2005-0767)

    Multiple range checking flaws were discovered in the iso9660 file system     handler. An attacker could create a malicious file system image which would     cause a denial or service or potentially execute arbitrary code if mounted.
    (CAN-2005-0815)

    A flaw was discovered when setting line discipline on a serial tty. A local     user may be able to use this flaw to inject mouse movements or keystrokes     when another user is logged in. (CAN-2005-0839)

    Red Hat Enterprise Linux 4 users are advised to upgrade their kernels     to the packages associated with their machine architectures and     configurations as listed in this erratum.

    Please note that

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
21928	CentOS 3 / 4 : kernel (CESA-2005:366)	Nessus	CentOS Local Security Checks	high
20497	Ubuntu 4.10 : linux-source-2.6.8.1 vulnerabilities (USN-110-1)	Nessus	Ubuntu Local Security Checks	high
18095	RHEL 4 : kernel (RHSA-2005:366)	Nessus	Red Hat Local Security Checks	high

Detections

Analytics

CVE-2005-0867

high

Tenable Plugins

high

high

high