Headline
Beware: Experts Reveal New Details on Zero-Click Outlook RCE Exploits
Technical details have emerged about two now-patched security flaws in Microsoft Windows that could be chained by threat actors to achieve remote code execution on the Outlook email service sans any user interaction. “An attacker on the internet can chain the vulnerabilities together to create a full, zero-click remote code execution (RCE) exploit against Outlook clients,” Akamai security
Email Security / Vulnerability
Technical details have emerged about two now-patched security flaws in Microsoft Windows that could be chained by threat actors to achieve remote code execution on the Outlook email service sans any user interaction.
“An attacker on the internet can chain the vulnerabilities together to create a full, zero-click remote code execution (RCE) exploit against Outlook clients,” Akamai security researcher Ben Barnea, who discovered the vulnerabilities, said in a two-part report shared with The Hacker News.
The security issues, which were addressed by Microsoft in August and October 2023, respectively, are listed below -
- CVE-2023-35384 (CVSS score: 5.4) - Windows HTML Platforms Security Feature Bypass Vulnerability
- CVE-2023-36710 (CVSS score: 7.8) - Windows Media Foundation Core Remote Code Execution Vulnerability
CVE-2023-35384 has been described by Akamai as a bypass for a critical security flaw that Microsoft patched in March 2023. Tracked as CVE-2023-23397 (CVSS score: 9.8), the flaw relates to a case of privilege escalation that could result in the theft of NTLM credentials and enable an attacker to conduct a relay attack.
Earlier this month, Microsoft, Proofpoint, and Palo Alto Networks Unit 42 revealed that a Russian threat actor known as APT29 has been actively weaponizing the bug to gain unauthorized access to victims’ accounts within Exchange servers.
It’s worth noting that CVE-2023-35384 is also the second patch bypass after CVE-2023-29324, which was also discovered by Barnea and subsequently remediated by Redmond as part of May 2023 security updates.
“We found another bypass to the original Outlook vulnerability — a bypass that once again allowed us to coerce the client to connect to an attacker-controlled server and download a malicious sound file,” Barnea said.
CVE-2023-35384, like CVE-2023-29324, is rooted in the parsing of a path by the MapUrlToZone function that could be exploited by sending an email containing a malicious file or a URL to an Outlook client.
“A security feature bypass vulnerability exists when the MSHTML platform fails to validate the correct Security Zone of requests for specific URLs. This could allow an attacker to cause a user to access a URL in a less restricted Internet Security Zone than intended,” Microsoft noted in its advisory.
In doing so, the vulnerability can not only be used to leak NTLM credentials, but can also be chained with the sound parsing flaw (CVE-2023-36710) to download a custom sound file that, when autoplayed using Outlook’s reminder sound feature, can lead to a zero-click code execution on the victim machine.
CVE-2023-36710 impacts the Audio Compression Manager (ACM) component, a legacy Windows multimedia framework that’s used to manage audio codecs, and is the result of an integer overflow vulnerability that occurs when playing a WAV file.
“Finally, we managed to trigger the vulnerability using the IMA ADP codec,” Barnea explained. “The file size is approximately 1.8 GB. By performing the math limit operation on the calculation we can conclude that the smallest possible file size with IMA ADP codec is 1 GB.”
To mitigate the risks, it’s recommended that organizations use microsegmentation to block outgoing SMB connections to remote public IP addresses. Additionally, it also advised to either disable NTLM, or add users to the Protected Users security group, which prevents the use of NTLM as an authentication mechanism.
Found this article interesting? Follow us on Twitter and LinkedIn to read more exclusive content we post.
Related news
By Waqas The #MonikerLink security flaw in Microsoft Outlook allows hackers to execute arbitrary code on the targeted device. This is a post from HackRead.com Read the original post: New MonikerLink Flaw Exposes Outlook Users to Data Theft and Malware
Russian state-sponsored actors have staged NT LAN Manager (NTLM) v2 hash relay attacks through various methods from April 2022 to November 2023, targeting high-value targets worldwide. The attacks, attributed to an "aggressive" hacking crew called APT28, have set their eyes on organizations dealing with foreign affairs, energy, defense, and transportation, as well as those involved with
A researcher found two Microsoft vulnerabilities which could be combined to achieve zero-click remote code execution.
Dell vApp Manger, versions prior to 9.2.4.x contain an arbitrary file read vulnerability. A remote attacker could potentially exploit this vulnerability to read arbitrary files from the target system.
Dell vApp Manger, versions prior to 9.2.4.x contain an arbitrary file read vulnerability. A remote attacker could potentially exploit this vulnerability to read arbitrary files from the target system.
The Russian nation-state threat actor known as APT28 has been observed making use of lures related to the ongoing Israel-Hamas war to facilitate the delivery of a custom backdoor called HeadLace. IBM X-Force is tracking the adversary under the name ITG05, which is also known as BlueDelta, Fancy Bear, Forest Blizzard (formerly Strontium), FROZENLAKE, Iron Twilight, Sednit, Sofacy, and
Microsoft on Monday said it detected Kremlin-backed nation-state activity exploiting a critical security flaw in its Outlook email service to gain unauthorized access to victims' accounts within Exchange servers. The tech giant attributed the intrusions to a threat actor it called Forest Blizzard (formerly Strontium), which is also widely tracked under the monikers APT28,
By Waqas Forest Blizzard (aka STRONTIUM, APT28, and Fancy Bear) is thought to have affiliations with or support from the Russian military intelligence agency. This is a post from HackRead.com Read the original post: Microsoft Outlook Vulnerability Exploited by Russian Forest Blizzard Group
Windows Media Foundation Core Remote Code Execution Vulnerability
Windows HTML Platforms Security Feature Bypass Vulnerability
Zero-day vulnerabilities in Windows Installers for the Atera remote monitoring and management software could act as a springboard to launch privilege escalation attacks. The flaws, discovered by Mandiant on February 28, 2023, have been assigned the identifiers CVE-2023-26077 and CVE-2023-26078, with the issues remediated in versions 1.8.3.7 and 1.8.4.9 released by Atera on April 17, 2023, and
Microsoft has disclosed that it's detected a spike in credential-stealing attacks conducted by the Russian state-affiliated hacker group known as Midnight Blizzard. The intrusions, which made use of residential proxy services to obfuscate the source IP address of the attacks, target governments, IT service providers, NGOs, defense, and critical manufacturing sectors, the tech giant's threat
Cybersecurity researchers have shared details about a now-patched security flaw in Windows MSHTML platform that could be abused to bypass integrity protections on targeted machines. The vulnerability, tracked as CVE-2023-29324 (CVSS score: 6.5), has been described as a security feature bypass. It was addressed by Microsoft as part of its Patch Tuesday updates for May 2023. Akamai security
Cybersecurity researchers have shared details about a now-patched security flaw in Windows MSHTML platform that could be abused to bypass integrity protections on targeted machines. The vulnerability, tracked as CVE-2023-29324 (CVSS score: 6.5), has been described as a security feature bypass. It was addressed by Microsoft as part of its Patch Tuesday updates for May 2023. Akamai security
Windows MSHTML Platform Security Feature Bypass Vulnerability
One of the vulnerabilities is being actively exploited in the wild, according to Microsoft, the fourth month in a row in which this is the case.
**According to the CVSS metric, successful exploitation of this vulnerability could lead to some loss of integrity (I:L) and some loss of availability (A:L). What does that mean for this vulnerability?** An attacker can craft a malicious URL that would evade zone checks, resulting in a limited loss of integrity and availability of the victim machine.
Snowballing PoC exploits for CVE-2023-23397 and a massive attack surface means almost business user could be a victim.
Security vendors urge organizations to fix the actively exploited bugs, in Microsoft Outlook and the Mark of the Web feature, immediately.
Microsoft disclosed 83 vulnerabilities across the company’s hardware and software line, including two issues that are actively being exploited in the wild, continuing a trend of zero-days appearing in Patch Tuesdays over the past few months.
May 9, 2023 update: Releases for Microsoft Products has been updated with the release of CVE-2023-29324 - Security Update Guide - Microsoft - Windows MSHTML Platform Security Feature Bypass Vulnerability March 24, 2023 update: Impact Assessment has been updated to a link to Guidance for investigating attacks using CVE-2023-23397 - Microsoft Security Blog.
**According to the CVSS metrics, successful exploitation of this vulnerability could lead to major loss of confidentiality (C:H), integrity (I:H) and availability (A:H). What does that mean for this vulnerability?** An attacker who successfully exploited this vulnerability could access a user's Net-NTLMv2 hash which could be used as a basis of an NTLM Relay attack against another service to authenticate as the user.