Finding and Fixing Vulnerabilities in OpenSSH Multiple Vulnerabilities , a Medium Risk Vulnerability

With Notes on Remediation, Penetration Testing, Disclosures, Patching and Exploits

Contents

  • Vital information on this issue
  • Scanning For and Finding multiple Vulnerabilities in Openssh
  • Penetration Testing (Pentest) for this Vulnerability
  • Security updates on multiple Vulnerabilities in Openssh
  • Disclosures related to multiple Vulnerabilities in Openssh
  • Confirming the Presence of multiple Vulnerabilities in Openssh
  • False positive/negatives
  • Patching/Repairing this vulnerability
  • Exploits related to multiple Vulnerabilities in Openssh

Vital Information on This Issue
multiple Vulnerabilities in Openssh is a Medium risk vulnerability that is one of the most frequently found on networks around the world. This issue has been around since at least 1990 but has proven either difficult to detect, difficult to resolve or prone to being overlooked entirely.


Vulnerability Name: Openssh
Test ID: 14035
Risk: Medium
Category: SSH servers
Type: Attack
Summary: The remote_glob function in sftp-glob.c and the process_put function in sftp.c in OpenSSH 5.8 and earlier, as used in FreeBSD 7.3 and 8.1, NetBSD 5.0.2, OpenBSD 4.7, and other products, allow remote authenticated users to cause a denial of service (CPU and memory consumption) via crafted glob expressions that do not match any pathnames, as demonstrated by glob expressions in SSH_FXP_STAT requests to an sftp daemon, a different vulnerability than CVE-2010-2632.

Other vulnerabilities may be flagged based on the version and are noted in the CVE list below.
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Impact: Allow remote authenticated users to cause a denial of service (CPU and memory consumption).
Solution: Upgrade to OpenSSH version 5.9 or newer.
CVE: CVE-2010-4755

CVE-2011-4327

CVE-2011-5000

CVE-2012-0814

More Information: http://cxsecurity.com/issue/WLB-2010100135

http://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2010-008.txt.asc

http://www.openssh.com/txt/portable-keysign-rand-helper.adv

https://bugzilla.redhat.com/show_bug.cgi?id=755640

Nist NVD (CVSS): AV:N/AC:L/Au:S/C:N/I:N/A:P
CVSS Score: 4.0
For more information on this also issue see: www.securiteam.com

Scanning For and Finding multiple Vulnerabilities in Openssh
Use of Vulnerability Management tools, like AVDS, are standard practice for the discovery of this vulnerability. The primary failure of VA in finding this vulnerability is related to setting the proper scope and frequency of network scans. It is vital that the broadest range of hosts (active IPs) possible are scanned and that scanning is done frequently. We recommend weekly. Your existing scanning solution or set of test tools should make this not just possible, but easy and affordable. If that is not the case, please consider AVDS.

Penetration Testing (pentest) for this Vulnerability
The multiple Vulnerabilities in Openssh is prone to false positive reports by most vulnerability assessment solutions. AVDS is alone in using behavior based testing that eliminates this issue. For all other VA tools security consultants will recommend confirmation by direct observation. In any case Penetration testing procedures for discovery of multiple Vulnerabilities in Openssh produces the highest discovery accuracy rate, but the infrequency of this expensive form of testing degrades its value. The ideal would be to have pentesting accuracy and the frequency and scope possibilities of VA solutions, and this is accomplished only by AVDS.

Security Updates on multiple Vulnerabilities in Openssh
For the most current updates on this vulnerability please check www.securiteam.com Given that this is one of the most frequently found vulnerabilities, there is ample information regarding mitigation online and very good reason to get it fixed. Hackers are also aware that this is a frequently found vulnerability and so its discovery and repair is that much more important. It is so well known and common that any network that has it present and unmitigated indicates "low hanging fruit" to attackers.

Disclosures related to this vulnerability

Confirming the Presence of multiple Vulnerabilities in Openssh
AVDS is currently testing for and finding this vulnerability with zero false positives. If your current set of tools is indicating that it is present but you think it is probably a false positive, please contact us for a demonstration of AVDS.

False positive/negatives
The secret killer of VA solution value is the false positive. There was an industry wide race to find the most vulnerabilities, including multiple Vulnerabilities in Openssh ,and this resulted in benefit to poorly written tests that beef up scan reports by adding a high percentage of uncertainty. This may have sold a lot of systems some years ago, but it also stuck almost all VA solutions with deliberately inaccurate reporting that adds time to repairs that no administrator can afford. Beyond Security did not participate in this race to mutually assured destruction of the industry and to this day produces the most accurate and actionable reports available.

Patching/Repairing this Vulnerability

multiple Vulnerabilities in Openssh is a Medium risk vulnerability that is also high frequency and high visibility. This is the most severe combination of security factors that exists and it is extremely important to find it on your network and fix it as soon as possible.

Exploits related to multiple Vulnerabilities in Openssh
http://www.cvedetails.com/product/585/Openbsd-Openssh.html?vendor_id=97
https://www.cvedetails.com/vulnerability-list/vendor_id-97/product_id-585/Openbsd-Openssh.html

Please also visit www.securiteam.com to view any exploits available for this vulnerability, or search using "multiple Vulnerabilities in Openssh ".


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