ZeroHour
Security Affairspublished ()ingested @securityaffairs

Microsoft Patch Tuesday addresses RDS flaw that opens to WannaCry

Vulnerabilities mentionedAll →

CVEVulnerabilityCVSSEPSSFlagsAffectedExposurePublished
CVE-2019-0708
Unauthenticated RCE in Microsoft Remote Desktop Services (BlueKeep)

CVE-2019-0708 is a use-after-free (CWE-416) vulnerability in Microsoft Remote Desktop Services, formerly Terminal Services, in which an unauthenticated attacker can connect to a target system over RDP and send specially crafted requests to trigger the flaw. Because the trigger requires no authentication, the flaw is wormable: a successful exploit grants remote code execution on the target host, potentially with elevated privileges, and could allow self-propagating attacks similar to WannaCry. Organizations running the affected Microsoft Remote Desktop Services, particularly legacy Windows releases still accepting inbound RDP connections, are in scope. Exploitation is confirmed in the wild: the flaw (nicknamed BlueKeep) is listed in CISA's KEV catalog (added 2021-11-03), CISA notes known ransomware use, and EPSS assigns it a 100% probability of exploitation within 30 days.

Do: Apply Microsoft's security updates for CVE-2019-0708 per vendor instructions, prioritizing legacy or end-of-support Windows systems exposed to inbound RDP. As mitigation, restrict RDP (TCP 3389) to trusted networks or VPN access, require Network Level Authentication (NLA), and audit perimeter firewalls and public scans for open RDP listeners. The vulnerability is in the CISA KEV catalog, so patching is treated as a required action for federal and high-risk environments.

9.8100% KEV ransomware PoC ×4
  • Microsoft Remote Desktop Services
masson the order of millions of internet-exposed RDP endpoints and far more internal systems
CVE-2019-0863
Local Privilege Escalation Flaw in Microsoft Windows Error Reporting (WER)

CVE-2019-0863 is an elevation of privilege vulnerability in Microsoft Windows Error Reporting (WER), caused by the way WER handles files on affected Windows releases. A local attacker who can already execute code on a vulnerable machine with limited privileges can trigger the flaw without user interaction and gain higher local privileges, with high impact on confidentiality, integrity, and availability per the CVSS vector. Anyone running the listed releases is affected: Windows 10 versions 1507 through 1903, Windows 7, Windows 8.1, Windows RT 8.1, and Windows Server versions 1803 and 1903; systems current on Microsoft's security updates are not vulnerable. The flaw is confirmed exploited in the wild — CISA added it to the Known Exploited Vulnerabilities catalog on 2021-11-03 (ransomware association unknown) — although no public proof-of-concept is known, and EPSS puts the 30-day exploitation probability at 5.2% (92nd percentile). The required action per CISA is to apply updates per vendor instructions.

Do: Apply Microsoft's security updates for each affected release as the CISA KEV entry requires; the flaw was fixed in 2019 cumulative updates, so any system current on monthly servicing is already protected. Prioritize patching multi-user and remote-access systems (RDS/VDI hosts, jump boxes, shared workstations) where low-privileged users can run code and escalate, and migrate unpatched Windows 7/8.1/RT 8.1 machines — many now past end of support — to a supported, patched Windows release.

7.85% KEV
  • microsoft Windows 10 1507, 1607, 1703, 1709, 1803, 1809, 1903
  • microsoft Windows 7
  • microsoft Windows 8.1
  • +3 more
masshundreds of thousands to millions of currently unpatched Windows endpoints (affected releases once ran on hundreds of millions of devices)
Full article633 words · extracted from securityaffairs.com · click to collapse

Microsoft Patch Tuesday updates for May 2019 address nearly 80 vulnerabilities, including an RDS flaw allowing WannaCry-Like attacks.

Microsoft Patch Tuesday updates for May 2019 address nearly 80 vulnerabilities, including a Windows zero-day flaw and an RDS vulnerability that can be exploited to carry out WannaCry-like attack.

The zero-day vulnerability addressed by Microsoft Patch Tuesday updates for May 2019 is a privilege escalation flaw related to the way the Windows Error Reporting (WER) system handles files. The vulnerability tracked as CVE-2019-0863 could be exploited by an attacker with low-privileged access to the targeted system to deliver a malware.

“An elevation of privilege vulnerability exists in the way Windows Error Reporting (WER) handles files. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with administrator privileges.” reads the security advisory published by Microsoft.

“To exploit the vulnerability, an attacker must first gain unprivileged execution on a victim system.”

The vulnerability was reported by experts at Palo Alto Networks and an expert who online with the moniker “Polar Bear.”

RDP flaw Microsoft Patch Tuesday

Microsoft Patch Tuesday updates for May 2019 also addresses a remote code execution flaw in Remote Desktop Services (RDS). The flaw tracked as CVE-2019-0708 can be exploited by an unauthenticated attacker by connecting to the targeted system via the Remote Desktop Protocol (RDP) and sending specially crafted requests.

“A remote code execution vulnerability exists in Remote Desktop Services – formerly known as Terminal Services – when an unauthenticated attacker connects to the target system using RDP and sends specially crafted requests.” reads the security advisory published by Microsoft. “This vulnerability is pre-authentication and requires no user interaction. An attacker who successfully exploited this vulnerability could execute arbitrary code on the target system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.”

“To exploit this vulnerability, an attacker would need to send a specially crafted request to the target systems Remote Desktop Service via RDP.”

It is important to highlight that the RDP itself is not vulnerable.

As explained by Microsoft, this vulnerability could be exploited by malware with wormable capabilities. It could be exploited by unautheticated attacker and without users interaction, making it possible for malware to spread in an uncontrolled way into the target networks.

The thought is for the WannaCry attack.

“This vulnerability is pre-authentication and requires no user interaction. 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.” reads a blog post published by Microsoft. “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.”

The vulnerability doesn’t affect Windows 8 and Windows 10, anyway previous versions are exposed to the risk of cyber attacks.

Microsoft Patch Tuesday updates for May 2019 also address vulnerabilities in Windows OS, Internet Explorer, Edge, Microsoft Office, and Microsoft Office Services and Web Apps, ChakraCore, .NET Framework, and ASP.NET, Skype for Android, Azure DevOps Server, and the NuGet Package Manager.

Microsoft released security updates for Windows 7, Windows Server 2008 R2, and Windows Server 2008, The tech giant has also separately released patches for out-of-support versions of Windows such as Windows 2003 and Windows XP.

18 vulnerabilities have been rated as critical and rest Important in severity. 

Microsoft also advised Windows Server users to block TCP port 3389 and enable Network Level Authentication to prevent any unauthenticated attacker from exploiting this vulnerability.

[adrotate banner=”9″] [adrotate banner=”12″]

Pierluigi Paganini

(SecurityAffairs – Windows, RDP)

[adrotate banner=”5″]

[adrotate banner=”13″]



Text extracted automatically; images, tables and formatting may be missing. Original: https://securityaffairs.com/85569/security/windows-rdp-flaw.html