Race condition in the do_add_counters function in netfilter for Linux kernel 2.6.16 allows local users with CAP_NET_ADMIN capabilities to read kernel memory by triggering the race condition in a way that produces a size value that is inconsistent with allocated memory, which leads to a buffer over-read in IPT_ENTRY_ITERATE.

Updated kernel packages that fix security issues 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 security issues described below :


From Red Hat Security Advisory 2006-0617 :

* a flaw in the proc file system that allowed a local user to use a suid-wrapper for scripts to gain root privileges (CVE-2006-3626, Important)

* a flaw in the SCTP implementation that allowed a local user to cause a denial of service (panic) or to possibly gain root privileges (CVE-2006-3745, Important)

* a flaw in NFS exported ext2/ext3 partitions when handling invalid inodes that allowed a remote authenticated user to cause a denial of service (filesystem panic) (CVE-2006-3468, Important)

* a flaw in the restore_all code path of the 4/4GB split support of non-hugemem kernels that allowed a local user to cause a denial of service (panic) (CVE-2006-2932, Important)

* a flaw in IPv4 netfilter handling for the unlikely use of SNMP NAT processing that allowed a remote user to cause a denial of service (crash) or potential memory corruption (CVE-2006-2444, Moderate)

* a flaw in the DVD handling of the CDROM driver that could be used together with a custom built USB device to gain root privileges (CVE-2006-2935, Moderate)

* a flaw in the handling of O_DIRECT writes that allowed a local user to cause a denial of service (memory consumption) (CVE-2004-2660, Low)

* a flaw in the SCTP chunk length handling that allowed a remote user to cause a denial of service (crash) (CVE-2006-1858, Low)

* a flaw in the input handling of the ftdi_sio driver that allowed a local user to cause a denial of service (memory consumption) (CVE-2006-2936, Low)

In addition a bugfix was added to enable a clean reboot for the IBM Pizzaro machines.

Red Hat would like to thank Wei Wang of McAfee Avert Labs and Kirill Korotaev for reporting issues fixed in this erratum.


From Red Hat Security Advisory ELSA-2006-0689 :

* a flaw in the SCTP support that allowed a local user to cause a denial of service (crash) with a specific SO_LINGER value.
(CVE-2006-4535, Important)

* a flaw in the hugepage table support that allowed a local user to cause a denial of service (crash). (CVE-2005-4811, Important)

* a flaw in the mprotect system call that allowed setting write permission for a read-only attachment of shared memory.
(CVE-2006-2071, Moderate)

* a flaw in HID0[31] (en_attn) register handling on PowerPC 970 systems that allowed a local user to cause a denial of service.
(crash) (CVE-2006-4093, Moderate)

* a flaw in the perfmon support of Itanium systems that allowed a local user to cause a denial of service by consuming all file descriptors. (CVE-2006-3741, Moderate)

* a flaw in the ATM subsystem. On systems with installed ATM hardware and configured ATM support, a remote user could cause a denial of service (panic) by accessing socket buffers memory after freeing them.
(CVE-2006-4997, Moderate)

* a flaw in the DVB subsystem. On systems with installed DVB hardware and configured DVB support, a remote user could cause a denial of service (panic) by sending a ULE SNDU packet with length of 0.
(CVE-2006-4623, Low)

* an information leak in the network subsystem that possibly allowed a local user to read sensitive data from kernel memory. (CVE-2006-0039, Low)

In addition, two bugfixes for the IPW-2200 wireless driver were included. The first one ensures that wireless management applications correctly identify IPW-2200 controlled devices, while the second fix ensures that DHCP requests using the IPW-2200 operate correctly.

Red Hat would like to thank Olof Johansson, Stephane Eranian and Solar Designer for reporting issues fixed in this erratum.

A race condition was discovered in the do_add_counters() functions.
Processes which do not run with full root privileges, but have the CAP_NET_ADMIN capability can exploit this to crash the machine or read a random piece of kernel memory. In Ubuntu there are no packages that are affected by this, so this can only be an issue for you if you use third-party software that uses Linux capabilities. (CVE-2006-0039)

John Stultz discovered a faulty BUG_ON trigger in the handling of POSIX timers. A local attacker could exploit this to trigger a kernel oops and crash the machine. (CVE-2006-2445)

Dave Jones discovered that the PowerPC kernel did not perform certain required access_ok() checks. A local user could exploit this to read arbitrary kernel memory and crash the kernel on 64-bit systems, and possibly read arbitrary kernel memory on 32-bit systems.
(CVE-2006-2448)

A design flaw was discovered in the prctl(PR_SET_DUMPABLE, ...) system call, which allowed a local user to have core dumps created in a directory he could not normally write to. This could be exploited to drain available disk space on system partitions, or, under some circumstances, to execute arbitrary code with full root privileges.
This flaw only affects Ubuntu 6.06 LTS. (CVE-2006-2451)

In addition, the Ubuntu 6.06 LTS update fixes a range of bugs.

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.

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-2005-3359     Franz Filz discovered that some socket calls permit     causing inconsistent reference counts on loadable     modules, which allows local users to cause a denial of     service.

  - CVE-2006-0038     'Solar Designer' discovered that arithmetic computations     in netfilter's do_replace() function can lead to a     buffer overflow and the execution of arbitrary code.
    However, the operation requires CAP_NET_ADMIN     privileges, which is only an issue in virtualization     systems or fine grained access control systems.

  - CVE-2006-0039     'Solar Designer' discovered a race condition in     netfilter's do_add_counters() function, which allows     information disclosure of kernel memory by exploiting a     race condition. Likewise, it requires CAP_NET_ADMIN     privileges. 

  - CVE-2006-0456     David Howells discovered that the s390 assembly version     of the strnlen_user() function incorrectly returns some     string size values.

  - CVE-2006-0554     It was discovered that the ftruncate() function of XFS     can expose unallocated blocks, which allows information     disclosure of previously deleted files.

  - CVE-2006-0555     It was discovered that some NFS file operations on     handles mounted with O_DIRECT can force the kernel into     a crash.

  - CVE-2006-0557     It was discovered that the code to configure memory     policies allows tricking the kernel into a crash, thus     allowing denial of service.

  - CVE-2006-0558     It was discovered by Cliff Wickman that perfmon for the     IA64 architecture allows users to trigger a BUG()     assert, which allows denial of service.

  - CVE-2006-0741     Intel EM64T systems were discovered to be susceptible to     a local DoS due to an endless recursive fault related to     a bad ELF entry address.

  - CVE-2006-0742     Alan and Gareth discovered that the ia64 platform had an     incorrectly declared die_if_kernel() function as 'does     never return' which could be exploited by a local     attacker resulting in a kernel crash.

  - CVE-2006-0744     The Linux kernel did not properly handle uncanonical     return addresses on Intel EM64T CPUs, reporting     exceptions in the SYSRET instead of the next     instruction, causing the kernel exception handler to run     on the user stack with the wrong GS. This may result in     a DoS due to a local user changing the frames.

  - CVE-2006-1056     AMD64 machines (and other 7th and 8th generation     AuthenticAMD processors) were found to be vulnerable to     sensitive information leakage, due to how they handle     saving and restoring the FOP, FIP, and FDP x87 registers     in FXSAVE/FXRSTOR when an exception is pending. This     allows a process to determine portions of the state of     floating point instructions of other processes.

  - CVE-2006-1242     Marco Ivaldi discovered that there was an unintended     information disclosure allowing remote attackers to     bypass protections against Idle Scans (nmap -sI) by     abusing the ID field of IP packets and bypassing the     zero IP ID in DF packet countermeasure. This was a     result of the ip_push_pending_frames function improperly     incremented the IP ID field when sending a RST after     receiving unsolicited TCP SYN-ACK packets.

  - CVE-2006-1368     Shaun Tancheff discovered a buffer overflow (boundary     condition error) in the USB Gadget RNDIS implementation     allowing remote attackers to cause a DoS. While creating     a reply message, the driver allocated memory for the     reply data, but not for the reply structure. The kernel     fails to properly bounds-check user-supplied data before     copying it to an insufficiently sized memory buffer.
    Attackers could crash the system, or possibly execute     arbitrary machine code.

  - CVE-2006-1523     Oleg Nesterov reported an unsafe BUG_ON call in signal.c     which was introduced by RCU signal handling. The BUG_ON     code is protected by siglock while the code in     switch_exit_pids() uses tasklist_lock. It may be     possible for local users to exploit this to initiate a     denial of service attack (DoS).

  - CVE-2006-1524     Hugh Dickins discovered an issue in the madvise_remove()     function wherein file and mmap restrictions are not     followed, allowing local users to bypass IPC permissions     and replace portions of readonly tmpfs files with     zeroes.

  - CVE-2006-1525     Alexandra Kossovsky reported a NULL pointer dereference     condition in ip_route_input() that can be triggered by a     local user by requesting a route for a multicast IP     address, resulting in a denial of service (panic).

  - CVE-2006-1857     Vlad Yasevich reported a data validation issue in the     SCTP subsystem that may allow a remote user to overflow     a buffer using a badly formatted HB-ACK chunk, resulting     in a denial of service.

  - CVE-2006-1858     Vlad Yasevich reported a bug in the bounds checking code     in the SCTP subsystem that may allow a remote attacker     to trigger a denial of service attack when rounded     parameter lengths are used to calculate parameter     lengths instead of the actual values.

  - CVE-2006-1863     Mark Mosely discovered that chroots residing on an CIFS     share can be escaped with specially crafted 'cd'     sequences.

  - CVE-2006-1864     Mark Mosely discovered that chroots residing on an SMB     share can be escaped with specially crafted 'cd'     sequences.

  - CVE-2006-2271     The 'Mu security team' discovered that carefully crafted     ECNE chunks can cause a kernel crash by accessing     incorrect state stable entries in the SCTP networking     subsystem, which allows denial of service.

  - CVE-2006-2272     The 'Mu security team' discovered that fragmented SCTP     control chunks can trigger kernel panics, which allows     for denial of service attacks.

  - CVE-2006-2274     It was discovered that SCTP packets with two initial     bundled data packets can lead to infinite recursion,     which allows for denial of service attacks.

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-2006-0038     'Solar Designer' discovered that arithmetic computations     in netfilter's do_replace() function can lead to a     buffer overflow and the execution of arbitrary code.
    However, the operation requires CAP_NET_ADMIN     privileges, which is only an issue in virtualization     systems or fine grained access control systems.

  - CVE-2006-0039     'Solar Designer' discovered a race condition in     netfilter's do_add_counters() function, which allows     information disclosure of kernel memory by exploiting a     race condition. Like CVE-2006-0038, it requires     CAP_NET_ADMIN privileges.

  - CVE-2006-0741     Intel EM64T systems were discovered to be susceptible to     a local DoS due to an endless recursive fault related to     a bad ELF entry address.

  - CVE-2006-0742     Incorrectly declared die_if_kernel() function as 'does     never return' which could be exploited by a local     attacker resulting in a kernel crash.

  - CVE-2006-1056     AMD64 machines (and other 7th and 8th generation     AuthenticAMD processors) were found to be vulnerable to     sensitive information leakage, due to how they handle     saving and restoring the FOP, FIP, and FDP x87 registers     in FXSAVE/FXRSTOR when an exception is pending. This     allows a process to determine portions of the state of     floating point instructions of other processes.

  - CVE-2006-1242     Marco Ivaldi discovered that there was an unintended     information disclosure allowing remote attackers to     bypass protections against Idle Scans (nmap -sI) by     abusing the ID field of IP packets and bypassing the     zero IP ID in DF packet countermeasure. This was a     result of the ip_push_pending_frames function improperly     incremented the IP ID field when sending a RST after     receiving unsolicited TCP SYN-ACK packets.

  - CVE-2006-1343     Pavel Kankovsky reported the existence of a potential     information leak resulting from the failure to     initialize sin.sin_zero in the IPv4 socket code.

  - CVE-2006-1368     Shaun Tancheff discovered a buffer overflow (boundary     condition error) in the USB Gadget RNDIS implementation     allowing remote attackers to cause a DoS. While creating     a reply message, the driver allocated memory for the     reply data, but not for the reply structure. The kernel     fails to properly bounds-check user-supplied data before     copying it to an insufficiently sized memory buffer.
    Attackers could crash the system, or possibly execute     arbitrary machine code.

  - CVE-2006-1524     Hugh Dickins discovered an issue in the madvise_remove()     function wherein file and mmap restrictions are not     followed, allowing local users to bypass IPC permissions     and replace portions of readonly tmpfs files with     zeroes.

  - CVE-2006-1525     Alexandra Kossovsky reported a NULL pointer dereference     condition in ip_route_input() that can be triggered by a     local user by requesting a route for a multicast IP     address, resulting in a denial of service (panic).

  - CVE-2006-1857     Vlad Yasevich reported a data validation issue in the     SCTP subsystem that may allow a remote user to overflow     a buffer using a badly formatted HB-ACK chunk, resulting     in a denial of service.

  - CVE-2006-1858     Vlad Yasevich reported a bug in the bounds checking code     in the SCTP subsystem that may allow a remote attacker     to trigger a denial of service attack when rounded     parameter lengths are used to calculate parameter     lengths instead of the actual values.

  - CVE-2006-1864     Mark Mosely discovered that chroots residing on an SMB     share can be escaped with specially crafted 'cd'     sequences.

  - CVE-2006-2271     The 'Mu security team' discovered that carefully crafted     ECNE chunks can cause a kernel crash by accessing     incorrect state stable entries in the SCTP networking     subsystem, which allows denial of service.

  - CVE-2006-2272     The 'Mu security team' discovered that fragmented SCTP     control chunks can trigger kernel panics, which allows     for denial of service attacks.

  - CVE-2006-2274     It was discovered that SCTP packets with two initial     bundled data packets can lead to infinite recursion,     which allows for denial of service attacks.

Updated kernel packages that fix several security issues in the Red Hat Enterprise Linux 4 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 security issues described below :

* a flaw in the SCTP support that allowed a local user to cause a denial of service (crash) with a specific SO_LINGER value.
(CVE-2006-4535, Important)

* a flaw in the hugepage table support that allowed a local user to cause a denial of service (crash). (CVE-2005-4811, Important)

* a flaw in the mprotect system call that allowed setting write permission for a read-only attachment of shared memory.
(CVE-2006-2071, Moderate)

* a flaw in HID0[31] (en_attn) register handling on PowerPC 970 systems that allowed a local user to cause a denial of service.
(crash) (CVE-2006-4093, Moderate)

* a flaw in the perfmon support of Itanium systems that allowed a local user to cause a denial of service by consuming all file descriptors. (CVE-2006-3741, Moderate)

* a flaw in the ATM subsystem. On systems with installed ATM hardware and configured ATM support, a remote user could cause a denial of service (panic) by accessing socket buffers memory after freeing them.
(CVE-2006-4997, Moderate)

* a flaw in the DVB subsystem. On systems with installed DVB hardware and configured DVB support, a remote user could cause a denial of service (panic) by sending a ULE SNDU packet with length of 0.
(CVE-2006-4623, Low)

* an information leak in the network subsystem that possibly allowed a local user to read sensitive data from kernel memory. (CVE-2006-0039, Low)

In addition, two bugfixes for the IPW-2200 wireless driver were included. The first one ensures that wireless management applications correctly identify IPW-2200 controlled devices, while the second fix ensures that DHCP requests using the IPW-2200 operate correctly.

Red Hat would like to thank Olof Johansson, Stephane Eranian and Solar Designer for reporting issues fixed in this erratum.

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.

The remote host is running Kerio MailServer version 6.0.10 or lower.  There is a flaw in the remote version of this server that would allow an attacker to cause the application to fail.  While the details of the flaw are unknown, it is alledged that an attacker can launch the attack without any credentials and render the target service unavailable.

The remote CentOS system is missing a security update which has been documented in Red Hat advisory RHSA-2006-0689.

ID	Name	Product	Family	Severity
67401	Oracle Linux 4 : kernel (ELSA-2006-0617 / ELSA-2006-0689)	Nessus	Oracle Linux Local Security Checks	high
27886	Ubuntu 5.04 / 5.10 / 6.06 LTS : linux-source-2.6.10/-2.6.12/-2.6.15 vulnerabilities (USN-311-1)	Nessus	Ubuntu Local Security Checks	medium
22645	Debian DSA-1103-1 : kernel-source-2.6.8 - several vulnerabilities	Nessus	Debian Local Security Checks	critical
22639	Debian DSA-1097-1 : kernel-source-2.4.27 - several vulnerabilities	Nessus	Debian Local Security Checks	critical
22523	RHEL 4 : kernel (RHSA-2006:0689)	Nessus	Red Hat Local Security Checks	high
22513	CentOS 4 : kernel (CESA-2006:0689)	Nessus	CentOS Local Security Checks	high
3469	Kerio MailServer < 6.1.3 Patch 1 Remote DoS	Nessus Network Monitor	SMTP Servers	medium
801422	CentOS RHSA-2006-0689 Security Check	Log Correlation Engine	Generic	high

Detections

Analytics

CVE-2006-0039

medium

Tenable Plugins

high

medium

critical

critical

high

high

medium

high