Hackers Exploiting Three Microsoft Office Flaws to Spread Zyklon Malware
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2017-11882 | Memory Corruption RCE in Microsoft Office via Legacy Equation Editor CVE-2017-11882 is a memory corruption vulnerability (CWE-119) in Microsoft Office, residing in the legacy Microsoft Equation Editor component (EQNEDT32.EXE), that allows remote code execution in the context of the current user. Attackers trigger it by persuading a user to open a crafted document, most commonly an RTF file or other Office document carrying a malicious embedded equation object, which overflows a buffer while the equation content is parsed. Successful exploitation lets the attacker run arbitrary code with the privileges of the signed-in user, a typical foothold for malware delivery and, per CISA, for ransomware operations. Any environment running affected Microsoft Office builds is exposed; the source data does not enumerate specific affected version ranges. The flaw is confirmed exploited in the wild: it was added to the CISA Known Exploited Vulnerabilities catalog on 2021-11-03 with known ransomware use and holds a 99.9% EPSS score (percentile 100), though the source data lists no public PoC. Do: Apply Microsoft's Office security updates (November 2017 or later) across all endpoints, prioritizing this KEV-listed flaw given its known ransomware use. On systems that cannot yet be patched, disable or unregister the legacy Equation Editor (EQNEDT32.EXE) and consider blocking or warning on RTF attachments as interim mitigations. Check for indicators of abuse such as EQNEDT32.EXE spawning unexpected child processes after document opens. | 7.8 | 100% | KEV ransomware PoC ×10 |
| masshundreds of millions of users/installations (Office is near-ubiquitous on Windows and in enterprises; the share still unpatched is unknown) | |
| CVE-2017-8759 | Remote Code Execution in Microsoft .NET Framework via Malicious Documents (CWE-94) CVE-2017-8759 is a code injection flaw (CWE-94) in Microsoft .NET Framework's handling of SOAP WSDL parsing, in which untrusted content referenced by a document or application is parsed and used during object instantiation, allowing attacker-controlled code to run. An attacker triggers it by delivering a specially crafted document — notably a Microsoft Word file referencing a malicious WSDL URL — and gets code execution when the document is opened and .NET downloads and parses the referenced content. Successful exploitation gives the attacker code execution with the privileges of the current user, sufficient to install malware, steal data, or facilitate further compromise. Any Windows system running .NET Framework versions 2.0, 3.5, 3.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, or 4.7 is affected, which at disclosure covered the vast majority of Windows desktops and servers in use. The flaw was a zero-day exploited in the wild at disclosure (September 2017, used in targeted attacks including BlackOasis), is listed in CISA's Known Exploited Vulnerabilities catalog, and public proof-of-concept exploits are available. Do: Apply Microsoft's security updates addressing this vulnerability to all affected .NET Framework versions on Windows endpoints and servers, per the CISA KEV required action. Prioritize user-facing systems that open documents and are internet-exposed, and verify installed .NET Framework versions before and after remediation. As a compensating control, exercise caution with untrusted documents and block or inspect outbound fetches of WSDL references embedded in Office files. | 7.8 | 89% | KEV PoC ×2 |
| masshundreds of millions of Windows devices (affected .NET Framework versions were enabled by default across broadly deployed Windows client and server releases) |
Indicators of compromiseauto-extracted · verify before use · export allAll →
| Type | Indicator | Context |
|---|---|---|
| ipv4 | 216.58.207.206 | llowing the decimal value. For example, Google's IP address 216.58.207.206 can also be represented as https://3627732942 in decimal va |
Full article632 words · extracted from thehackernews.com · click to collapse
The Hacker NewsJan 17, 2018
Security researchers have spotted a new malware campaign in the wild that spreads an advanced botnet malware by leveraging at least three recently disclosed vulnerabilities in Microsoft Office.
Dubbed Zyklon, the fully-featured malware has resurfaced after almost two years and primarily found targeting telecommunications, insurance and financial services.
Active since early 2016, Zyklon is an HTTP botnet malware that communicates with its command-and-control servers over Tor anonymising network and allows attackers to remotely steal keylogs, sensitive data, like passwords stored in web browsers and email clients.
Zyklon malware is also capable of executing additional plugins, including secretly using infected systems for DDoS attacks and cryptocurrency mining.
Different versions of the Zyklon malware has previously been found being advertised on a popular underground marketplace for $75 (normal build) and $125 ( Tor-enabled build).
According to a recently published report by FireEye, the attackers behind the campaign are leveraging three following vulnerabilities in Microsoft Office that execute a PowerShell script on the targeted computers to download the final payload from its C&C server.
1) .NET Framework RCE Vulnerability (CVE-2017-8759)—this remote code execution vulnerability exists when Microsoft .NET Framework processes untrusted input, allowing an attacker to take control of an affected system by tricking victims into opening a specially crafted malicious document file sent over an email. Microsoft already released a security patch for this flaw in September updates.
2) Microsoft Office RCE Vulnerability (CVE-2017-11882)—it’s a 17-year-old memory corruption flaw that Microsoft patched in November patch update allows a remote attacker to execute malicious code on the targeted systems without requiring any user interaction after opening a malicious document.
3) Dynamic Data Exchange Protocol (DDE Exploit)—this technique allows attackers to leverage a built-in feature of Microsoft Office, called DDE, to perform code execution on the targeted device without requiring Macros to be enabled or memory corruption.
As explained by the researchers, attackers are actively exploiting these three vulnerabilities to deliver Zyklon malware using spear phishing emails, which typically arrives with an attached ZIP file containing a malicious Office doc file.
Once opened, the malicious doc file equipped with one of these vulnerabilities immediately runs a PowerShell script, which eventually downloads the final payload, i.e., Zyklon HTTP malware, onto the infected computer.
"In all these techniques, the same domain is used to download the next level payload (Pause.ps1), which is another PowerShell script that is Base64 encoded," the FireEye researchers said.
"The Pause.ps1 script is responsible for resolving the APIs required for code injection. It also contains the injectable shellcode."
"The injected code is responsible for downloading the final payload from the server. The final stage payload is a PE executable compiled with .Net framework."
Interestingly, the PowerShell script connects to a dotless IP address (example: https://3627732942) to download the final payload.
What is Dotless IP Address? If you are unaware, dotless IP addresses, sometimes referred as 'Decimal Address,' are decimal values of IPv4 addresses (represented as dotted-quad notation). Almost all modern web browsers resolve decimal IP address to its equivalent IPV4 address when opened with "https://" following the decimal value.
For example, Google's IP address 216.58.207.206 can also be represented as https://3627732942 in decimal values (Try this online converter).
The best way to protect yourself and your organisation from such malware attacks are always to be suspicious of any uninvited document sent via an email and never click on links inside those documents unless adequately verifying the source.
Most importantly, always keep your software and systems up-to-date, as threat actors incorporate recently discovered, but patched, vulnerabilities in popular software—Microsoft Office, in this case—to increase the potential for successful infections.
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Text extracted automatically; images, tables and formatting may be missing. Original: https://thehackernews.com/2018/01/microsoft-office-malware.html