The shmctl function in Linux 2.6.9 and earlier allows local users to unlock the memory of other processes, which could cause sensitive memory to be swapped to disk, which could allow it to be read by other users once it has been released.

Updated kernel packages that fix several security issues in the Red Hat Enterprise Linux 3 kernel are now available.

This security advisory 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 three security issues described below as well as an important fix for a problem that could lead to data corruption on x86-architecture SMP systems with greater than 4GB of memory through heavy usage of multi-threaded applications.

A flaw between execve() syscall handling and core dumping of ELF-format executables allowed local unprivileged users to cause a denial of service (system crash) or possibly gain privileges. The Common Vulnerabilities and Exposures project has assigned the name CVE-2005-1263 to this issue.

A flaw in shared memory locking allowed local unprivileged users to lock and unlock regions of shared memory segments they did not own (CVE-2005-0176).

A flaw in the locking of SysV IPC shared memory regions allowed local unprivileged users to bypass their RLIMIT_MEMLOCK resource limit (CVE-2004-0491).

Note: The kernel-unsupported package contains various drivers and modules that are unsupported and therefore might contain security problems that have not been addressed.

All Red Hat Enterprise Linux 3 users are advised to upgrade their kernels to the packages associated with their machine architectures and configurations as listed in this erratum.

Please also consult the RHEL3 Update 5 advisory RHSA-2005:294 for the complete list of features added and bugs fixed in U5, which was released only a week prior to this security update.

CAN-2004-0176 :

Michael Kerrisk noticed an insufficient permission checking in the shmctl() function. Any process was permitted to lock/unlock any System V shared memory segment that fell within the the RLIMIT_MEMLOCK limit (that is the maximum size of shared memory that unprivileged users can acquire). This allowed am unprivileged user process to unlock locked memory of other processes, thereby allowing them to be swapped out.
Usually locked shared memory is used to store passphrases and other sensitive content which must not be written to the swap space (where it could be read out even after a reboot).

CAN-2005-0177 :

OGAWA Hirofumi noticed that the table sizes in nls_ascii.c were incorrectly set to 128 instead of 256. This caused a buffer overflow in some cases which could be exploited to crash the kernel.

CAN-2005-0178 :

A race condition was found in the terminal handling of the 'setsid()' function, which is used to start new process sessions.

http://oss.sgi.com/archives/netdev/2005-01/msg01036.html :

David Coulson noticed a design flaw in the netfilter/iptables module.
By sending specially crafted packets, a remote attacker could exploit this to crash the kernel or to bypass firewall rules.

Fixing this vulnerability required a change in the Application Binary Interface (ABI) of the kernel. This means that third-party user installed modules might not work any more with the new kernel, so this fixed kernel has a new ABI version number. You have to recompile and reinstall all third-party modules.

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-2005:092 advisory.

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

    This advisory includes fixes for several security issues:

    iSEC Security Research discovered multiple vulnerabilities in the IGMP     functionality.  These flaws could allow a local user to cause a denial of     service (crash) or potentially gain privileges.  Where multicast     applications are being used on a system, these flaws may also allow remote     users to cause a denial of service.  The Common Vulnerabilities and     Exposures project (cve.mitre.org) has assigned the name CAN-2004-1137 to     this issue.

    iSEC Security Research discovered a flaw in the page fault handler code     that could lead to local users gaining elevated (root) privileges on     multiprocessor machines.  (CAN-2005-0001)

    iSEC Security Research discovered a VMA handling flaw in the uselib(2)     system call of the Linux kernel.  A local user could make use of this     flaw to gain elevated (root) privileges.  (CAN-2004-1235)

    A flaw affecting the OUTS instruction on the AMD64 and Intel EM64T     architecture was discovered.  A local user could use this flaw to write to     privileged IO ports.  (CAN-2005-0204)

    The Direct Rendering Manager (DRM) driver in Linux kernel 2.6 does not     properly check the DMA lock, which could allow remote attackers or local     users to cause a denial of service (X Server crash) or possibly modify the     video output. (CAN-2004-1056)

    OGAWA Hirofumi discovered incorrect tables sizes being used in the     filesystem Native Language Support ASCII translation table.  This could     lead to a denial of service (system crash).  (CAN-2005-0177)

    Michael Kerrisk discovered a flaw in the 2.6.9 kernel which allows users to     unlock arbitrary shared memory segments.  This flaw could lead to     applications not behaving as expected.  (CAN-2005-0176)

    Improvements in the POSIX signal and tty standards compliance exposed     a race condition.  This flaw can be triggered accidentally by threaded     applications or deliberately by a malicious user and can result in a     denial of service (crash) or in occasional cases give access to a small     random chunk of kernel memory.  (CAN-2005-0178)

    The PaX team discovered a flaw in mlockall introduced in the 2.6.9 kernel.
    An unprivileged user could use this flaw to cause a denial of service     (CPU and memory consumption or crash).  (CAN-2005-0179)

    Brad Spengler discovered multiple flaws in sg_scsi_ioctl in the 2.6 kernel.
    An unprivileged user may be able to use this flaw to cause a denial of     service (crash) or possibly other actions.  (CAN-2005-0180)

    Kirill Korotaev discovered a missing access check regression in the Red Hat     Enterprise Linux 4 kernel 4GB/4GB split patch.  On systems using the     hugemem kernel, a local unprivileged user could use this flaw to cause a     denial of service (crash).  (CAN-2005-0090)

    A flaw in the Red Hat Enterprise Linux 4 kernel 4GB/4GB split patch can     allow syscalls to read and write arbitrary kernel memory.  On systems using     the hugemem kernel, a local unprivileged user could use this flaw to gain     privileges.  (CAN-2005-0091)

    An additional flaw in the Red Hat Enterprise Linux 4 kernel 4GB/4GB split     patch was discovered. On x86 systems using the hugemem kernel, a local     unprivileged user may be able to use this flaw to cause a denial of service     (crash).  (CAN-2005-0092)

    All 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.

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
21828	CentOS 3 : kernel (CESA-2005:472)	Nessus	CentOS Local Security Checks	high
20706	Ubuntu 4.10 : linux-source-2.6.8.1 vulnerabilities (USN-82-1)	Nessus	Ubuntu Local Security Checks	high
18389	RHEL 3 : kernel (RHSA-2005:472)	Nessus	Red Hat Local Security Checks	high
17183	RHEL 4 : kernel (RHSA-2005:092)	Nessus	Red Hat Local Security Checks	high

Detections

Analytics

CVE-2005-0176

medium

Tenable Plugins

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high

high

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