Time to Patch


14
Jan 20

Patch Tuesday, January 2020 Edition

Microsoft today released updates to plug 50 security holes in various flavors of Windows and related software. The patch batch includes a fix for a flaw in Windows 10 and server equivalents of this operating system that prompted an unprecedented public warning from the U.S. National Security Agency. This month also marks the end of mainstream support for Windows 7, a still broadly-used operating system that will no longer be supplied with security updates.

As first reported Monday by KrebsOnSecurity, Microsoft addressed a severe bug (CVE-2020-0601) in Windows 10 and Windows Server 2016/19 reported by the NSA that allows an attacker to spoof the digital signature tied to a specific piece of software. Such a weakness could be abused by attackers to make malware appear to be a benign program that was produced and signed by a legitimate software company.

An advisory (PDF) released today by the NSA says the flaw may have far more wide-ranging security implications, noting that the “exploitation of the vulnerability allows attackers to defeat trusted network connections and deliver executable code while appearing as legitimately trusted entities.”

“NSA assesses the vulnerability to be severe and that sophisticated cyber actors will understand the underlying flaw very quickly and, if exploited, would render the previously mentioned platforms as fundamentally vulnerable,” the advisory continues. “The consequences of not patching the vulnerability are severe and widespread.”

Matthew Green, an associate professor in the computer science department at Johns Hopkins University, said the flaw involves an apparent implementation weakness in a component of recent Windows versions responsible for validating the legitimacy of authentication requests for a panoply of security functions in the operating system.

Green said attackers can use this weakness to impersonate everything from trusted Web sites to the source of software updates for Windows and other programs.

“Imagine if I wanted to pick the lock in your front door,” Green analogized. “It might be hard for me to come up with a key that will open your door, but what if I could tamper with or present both the key and the lock at the same time?”

Kenneth White, security principal at the software company MongoDB, equated the vulnerability to a phone call that gets routed to a party you didn’t intend to reach.

“You pick up the phone, dial a number and assume you’re talking to your bank or Microsoft or whomever, but the part of the software that confirms who you’re talking to is flawed,” White said. “That’s pretty bad, especially when your system is saying download this piece of software or patch automatically and it’s being done in the background.”

Both Green and White said it likely will be a matter of hours or days before security researchers and/or bad guys work out ways to exploit this bug, given the stakes involved. Indeed, already this evening KrebsOnSecurity has seen indications that people are teasing out such methods, which will likely be posted publicly online soon. Continue reading →


13
Jan 20

Cryptic Rumblings Ahead of First 2020 Patch Tuesday

Sources tell KrebsOnSecurity that Microsoft Corp. is slated to release a software update on Tuesday to fix an extraordinarily serious security vulnerability in a core cryptographic component present in all versions of Windows. Those sources say Microsoft has quietly shipped a patch for the bug to branches of the U.S. military and to other high-value customers/targets that manage key Internet infrastructure, and that those organizations have been asked to sign agreements preventing them from disclosing details of the flaw prior to Jan. 14, the first Patch Tuesday of 2020.

According to sources, the vulnerability in question resides in a Windows component known as crypt32.dll, a Windows module that Microsoft says handles “certificate and cryptographic messaging functions in the CryptoAPI.” The Microsoft CryptoAPI provides services that enable developers to secure Windows-based applications using cryptography, and includes functionality for encrypting and decrypting data using digital certificates.

A critical vulnerability in this Windows component could have wide-ranging security implications for a number of important Windows functions, including authentication on Windows desktops and servers, the protection of sensitive data handled by Microsoft’s Internet Explorer/Edge browsers, as well as a number of third-party applications and tools.

Equally concerning, a flaw in crypt32.dll might also be abused to spoof the digital signature tied to a specific piece of software. Such a weakness could be exploited by attackers to make malware appear to be a benign program that was produced and signed by a legitimate software company.

This component was introduced into Windows more than 20 years ago — back in Windows NT 4.0. Consequently, all versions of Windows are likely affected (including Windows XP, which is no longer being supported with patches from Microsoft).

Microsoft has not yet responded to requests for comment. However, KrebsOnSecurity has heard rumblings from several sources over the past 48 hours that this Patch Tuesday (tomorrow) will include a doozy of an update that will need to be addressed immediately by all organizations running Windows.

Update 7:49 p.m. ET: Microsoft responded, saying that it does not discuss the details of reported vulnerabilities before an update is available. The company also said it does “not release production-ready updates ahead of regular Update Tuesday schedule. “Through our Security Update Validation Program (SUVP), we release advance versions of our updates for the purpose of validation and interoperability testing in lab environments,” Microsoft said in a written statement. “Participants in this program are contractually disallowed from applying the fix to any system outside of this purpose and may not apply it to production infrastructure.”

Continue reading →


10
Dec 19

Patch Tuesday, December 2019 Edition

Microsoft today released updates to plug three dozen security holes in its Windows operating system and other software. The patches include fixes for seven critical bugs — those that can be exploited by malware or miscreants to take control over a Windows system with no help from users — as well as another flaw in most versions of Windows that is already being exploited in active attacks.

By nearly all accounts, the chief bugaboo this month is CVE-2019-1458, a vulnerability in a core Windows component (Win32k) that is present in Windows 7 through 10 and Windows Server 2008-2019. This bug is already being exploited in the wild, and according to Recorded Future the exploit available for it is similar to CVE-2019-0859, a Windows flaw reported in April that was found being sold in underground markets.

CVE-2019-1458 is what’s known as a “privilege escalation” flaw, meaning an attacker would need to previously have compromised the system using another vulnerability. Handy in that respect is CVE-2019-1468, a similarly widespread critical issue in the Windows font library that could be exploited just by getting the user to visit a hacked or malicious Web site.

Chris Goettl, director of security at Ivanti, called attention to a curious patch advisory Microsoft released today for CVE-2019-1489, which is yet another weakness in the Windows Remote Desktop Protocol (RDP) client, a component of Windows that lets users view and manage their system from a remote computer. What’s curious about this advisory is that it applies only to Windows XP Service Pack 3, which is no longer receiving security updates.

“The Exploitability Assessment for Latest Software Release and Older Software Release is 0, which is usually the value reserved for a vulnerability that is known to be exploited, yet the Exploited value was currently set to ‘No’ as the bulletin was released today,” Goettl said. “If you look at the Zero Day from this month (CVE-2019-1458) the EA for Older Software Release is ‘0 – Exploitation Detected.’ An odd discrepancy on top of a CVE advisory for an outdated OS. It is very likely this is being exploited in the wild.”

Microsoft didn’t release a patch for this bug on XP, and its advisory on it is about as sparse as they come. But if you’re still depending on Windows XP for remote access, you likely have bigger security concerns. Microsoft has patched many critical RDP flaws in the past year. Even the FBI last year encouraged users to disable it unless needed, citing flawed encryption mechanisms in older versions and a lack of access controls which make RDP a frequent entry point for malware and ransomware. Continue reading →


12
Nov 19

Patch Tuesday, November 2019 Edition

Microsoft today released updates to plug security holes in its software, including patches to fix at least 74 weaknesses in various flavors of Windows and programs that run on top of it. The November updates include patches for a zero-day flaw in Internet Explorer that is currently being exploited in the wild, as well as a sneaky bug in certain versions of Office for Mac that bypasses security protections and was detailed publicly prior to today’s patches.

More than a dozen of the flaws tackled in this month’s release are rated “critical,” meaning they involve weaknesses that could be exploited to install malware without any action on the part of the user, except for perhaps browsing to a hacked or malicious Web site or opening a booby-trapped file attachment.

Perhaps the most concerning of those critical holes is a zero-day flaw in Internet Exploder Explorer (CVE-2019-1429) that has already seen active exploitation. Today’s updates also address two other critical vulnerabilities in the same Windows component that handles various scripting languages.

Microsoft also fixed a flaw in Microsoft Office for Mac (CVE-2019-1457) that could allow attackers to bypass security protections in some versions of the program.

Macros are bits of computer code that can be embedded into Office files, and malicious macros are frequently used by malware purveyors to compromise Windows systems. Usually, this takes the form of a prompt urging the user to “enable macros” once they’ve opened a booby-trapped Office document delivered via email. Thus, Office has a feature called “disable all macros without notification.”

But Microsoft says all versions of Office still support an older type of macros that do not respect this setting, and can be used as a vector for pushing malwareWill Dormann of the CERT/CC has reported that Office 2016 and 2019 for Mac will fail to prompt the user before executing these older macro types if the “Disable all macros without notification” setting is used. Continue reading →


9
Oct 19

Patch Tuesday Lowdown, October 2019 Edition

On Tuesday Microsoft issued software updates to fix almost five dozen security problems in Windows and software designed to run on top of it. By most accounts, it’s a relatively light patch batch this month. Here’s a look at the highlights.

Happily, only about 15 percent of the bugs patched this week earned Microsoft’s most dire “critical” rating. Microsoft labels flaws critical when they could be exploited by miscreants or malware to seize control over a vulnerable system without any help from the user.

Also, Adobe has kindly granted us another month’s respite from patching security holes in its Flash Player browser plugin.

Included in this month’s roundup is something Microsoft actually first started shipping in the third week of September, when it released an emergency update to fix a critical Internet Explorer zero-day flaw (CVE-2019-1367) that was being exploited in the wild. Continue reading →


10
Sep 19

Patch Tuesday, September 2019 Edition

Microsoft today issued security updates to plug some 80 security holes in various flavors of its Windows operating systems and related software. The software giant assigned a “critical” rating to almost a quarter of those vulnerabilities, meaning they could be used by malware or miscreants to hijack vulnerable systems with little or no interaction on the part of the user.

Two of the bugs quashed in this month’s patch batch (CVE-2019-1214 and CVE-2019-1215) involve vulnerabilities in all supported versions of Windows that have already been exploited in the wild. Both are known as “privilege escalation” flaws in that they allow an attacker to assume the all-powerful administrator status on a targeted system. Exploits for these types of weaknesses are often deployed along with other attacks that don’t require administrative rights.

September also marks the fourth time this year Microsoft has fixed critical bugs in its Remote Desktop Protocol (RDP) feature, with four critical flaws being patched in the service. According to security vendor Qualys, these Remote Desktop flaws were discovered in a code review by Microsoft, and in order to exploit them an attacker would have to trick a user into connecting to a malicious or hacked RDP server.

Microsoft also fixed another critical vulnerability in the way Windows handles link files ending in “.lnk” that could be used to launch malware on a vulnerable system if a user were to open a removable drive or access a shared folder with a booby-trapped .lnk file on it.

Shortcut files — or those ending in the “.lnk” extension — are Windows files that link easy-to-recognize icons to specific executable programs, and are typically placed on the user’s Desktop or Start Menu. It’s perhaps worth noting that poisoned .lnk files were one of the four known exploits bundled with Stuxnet, a multi-million dollar cyber weapon that American and Israeli intelligence services used to derail Iran’s nuclear enrichment plans roughly a decade ago.

In last month’s Microsoft patch dispatch, I ruefully lamented the utter hose job inflicted on my Windows 10 system by the July round of security updates from Redmond. Many readers responded by saying one or another updates released by Microsoft in August similarly caused reboot loops or issues with Windows repeatedly crashing.

As there do not appear to be any patch-now-or-be-compromised-tomorrow flaws in the September patch rollup, it’s probably safe to say most Windows end-users would benefit from waiting a few days to apply these fixes.  Continue reading →


13
Aug 19

Patch Tuesday, August 2019 Edition

Most Microsoft Windows (ab)users probably welcome the monthly ritual of applying security updates about as much as they look forward to going to the dentist: It always seems like you were there just yesterday, and you never quite know how it’s all going to turn out. Fortunately, this month’s patch batch from Redmond is mercifully light, at least compared to last month.

Okay, maybe a trip to the dentist’s office is still preferable. In any case, today is the second Tuesday of the month, which means it’s once again Patch Tuesday (or — depending on your setup and when you’re reading this post — Reboot Wednesday). Microsoft today released patches to fix some 93 vulnerabilities in Windows and related software, 35 of which affect various Server versions of Windows, and another 70 that apply to the Windows 10 operating system.

Although there don’t appear to be any zero-day vulnerabilities fixed this month — i.e. those that get exploited by cybercriminals before an official patch is available — there are several issues that merit attention.

Chief among those are patches to address four moderately terrifying flaws in Microsoft’s Remote Desktop Service, a feature which allows users to remotely access and administer a Windows computer as if they were actually seated in front of the remote computer. Security vendor Qualys says two of these weaknesses can be exploited remotely without any authentication or user interaction.

“According to Microsoft, at least two of these vulnerabilities (CVE-2019-1181 and CVE-2019-1182) can be considered ‘wormable’ and [can be equated] to BlueKeep,” referring to a dangerous bug patched earlier this year that Microsoft warned could be used to spread another WannaCry-like ransomware outbreak. “It is highly likely that at least one of these vulnerabilities will be quickly weaponized, and patching should be prioritized for all Windows systems.”

Fortunately, Remote Desktop is disabled by default in Windows 10, and as such these flaws are more likely to be a threat for enterprises that have enabled the application for various purposes. For those keeping score, this is the fourth time in 2019 Microsoft has had to fix critical security issues with its Remote Desktop service.

For all you Microsoft Edge and Internet Exploiter Explorer users, Microsoft has issued the usual panoply of updates for flaws that could be exploited to install malware after a user merely visits a hacked or booby-trapped Web site. Other equally serious flaws patched in Windows this month could be used to compromise the operating system just by convincing the user to open a malicious file (regardless of which browser the user is running). Continue reading →


9
Jul 19

Patch Tuesday Lowdown, July 2019 Edition

Microsoft today released software updates to plug almost 80 security holes in its Windows operating systems and related software. Among them are fixes for two zero-day flaws that are actively being exploited in the wild, and patches to quash four other bugs that were publicly detailed prior to today, potentially giving attackers a head start in working out how to use them for nefarious purposes.

Zero-days and publicly disclosed flaws aside for the moment, probably the single most severe vulnerability addressed in this month’s patch batch (at least for enterprises) once again resides in the component of Windows responsible for automatically assigning Internet addresses to host computers — a function called the “Windows DHCP server.”

The DHCP weakness (CVE-2019-0785) exists in most supported versions of Windows server, from Windows Server 2012 through Server 2019.

Microsoft said an unauthenticated attacker could use the DHCP flaw to seize total, remote control over vulnerable systems simply by sending a specially crafted data packet to a Windows computer. For those keeping count, this is the fifth time this year that Redmond has addressed such a critical flaw in the Windows DHCP client.

All told, only 15 of the 77 flaws fixed today earned Microsoft’s most dire “critical” rating, a label assigned to flaws that malware or miscreants could exploit to commandeer computers with little or no help from users. It should be noted that 11 of the 15 critical flaws are present in or are a key component of the browsers built into Windows — namely, Edge and Internet Exploder Explorer. Continue reading →


12
Jun 19

Microsoft Patch Tuesday, June 2019 Edition

Microsoft on Tuesday released updates to fix 88 security vulnerabilities in its Windows operating systems and related software. The most dangerous of these include four flaws for which there is already exploit code available. There’s also a scary bug affecting all versions of Microsoft Office that can be triggered by a malicious link or attachment. And of course Adobe has its customary monthly security update for Flash Player.

Microsoft says it has so far seen no exploitation against any of the four flaws that were disclosed publicly prior to their patching this week — nor against any of the 88 bugs quashed in this month’s release. All four are privilege escalation flaws: CVE-2019-1064 and CVE-2019-1069 affect Windows 10 and later; CVE-2019-1053 and CVE-2019-0973 both affect all currently supported versions of Windows.

Most of the critical vulnerabilities — those that can be exploited by malware or miscreants to infect systems without any action on the part of the user — are present in Microsoft’s browsers Internet Explorer and Edge.

According to Allan Liska, senior solutions architect at Recorded Future, serious vulnerabilities in this month’s patch batch reside in Microsoft Word (CVE-2019-1034 and CVE-2019-1035).

“This is another memory corruption vulnerability that requires an attacker to send a specially crafted Microsoft Word document for a victim to open, alternatively an attacker could convince a victim to click on a link to a website hosting a malicious Microsoft Word document,” Liska wrote. “This vulnerability affects all versions of Microsoft Word on Windows and Mac as well as Office 365. Given that Microsoft Word Documents are a favorite exploitation tool of cybercriminals, if this vulnerability is reverse engineered it could be widely exploited.” Continue reading →


14
May 19

Microsoft Patches ‘Wormable’ Flaw in Windows XP, 7 and Windows 2003

Microsoft today is taking the unusual step of releasing security updates for unsupported but still widely-used Windows operating systems like XP and Windows 2003, citing the discovery of a “wormable” flaw that the company says could be used to fuel a fast-moving malware threat like the WannaCry ransomware attacks of 2017.

The May 2017 global malware epidemic WannaCry affected some 200,000 Windows systems in 150 countries. Source: Wikipedia.

The vulnerability (CVE-2019-0708) resides in the “remote desktop services” component built into supported versions of Windows, including Windows 7, Windows Server 2008 R2, and Windows Server 2008. It also is present in computers powered by Windows XP and Windows 2003, operating systems for which Microsoft long ago stopped shipping security updates.

Microsoft said the company has not yet observed any evidence of attacks against the dangerous security flaw, but that it is trying to head off a serious and imminent threat.

“While we have observed no exploitation of this vulnerability, it is highly likely that malicious actors will write an exploit for this vulnerability and incorporate it into their malware,” wrote Simon Pope, director of incident response for the Microsoft Security Response Center.

“This vulnerability is pre-authentication and requires no user interaction,” Pope said. “In other words, the vulnerability is ‘wormable,’ meaning that any future malware that exploits this vulnerability could propagate from vulnerable computer to vulnerable computer in a similar way as the WannaCry malware spread across the globe in 2017. It is important that affected systems are patched as quickly as possible to prevent such a scenario from happening.”

The WannaCry ransomware threat spread quickly across the world in May 2017 using a vulnerability that was particularly prevalent among systems running Windows XP and older versions of Windows. Microsoft had already released a patch for the flaw, but many older and vulnerable OSes were never updated. Europol estimated at the time that WannaCry spread to some 200,000 computers across 150 countries. Continue reading →