Blue Mockingbird Monero
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2019-18935 | Unauthenticated .NET Deserialization RCE in Progress Telerik UI for ASP.NET AJAX CVE-2019-18935 is a .NET deserialization flaw (CWE-502) in the RadAsyncUpload function of Progress Telerik UI for ASP.NET AJAX through version 2019.3.1023. It is triggered when an attacker who knows the Telerik upload encryption keys — most commonly because the earlier flaws CVE-2017-11317 or CVE-2017-11357 exposed them, though keys can be obtained by other means — sends crafted serialized data to RadAsyncUpload, allowing remote code execution without authentication. Successful exploitation gives an attacker arbitrary code execution on the hosting IIS/ASP.NET web server, reflected in the critical 9.8 CVSS score. Any web application built with Telerik UI for ASP.NET AJAX at or below 2019.3.1023 is affected, unless 2019.3.1023 has the non-default hardening setting enabled (as of 2020.1.114 a default setting prevents the exploit). Exploitation is rampant in the wild: the flaw was added to CISA KEV on 2021-11-03 with known ransomware use, carries a 99.7% EPSS probability of exploitation, has multiple public exploits (Bishop Fox, RAU_crypto, noperator), and has been used by multiple threat groups — including ransomware and government-linked actors — to breach organizations including a U.S. federal agency. Do: Upgrade to Progress Telerik UI for ASP.NET AJAX 2020.1.114 or later, where a default setting prevents exploitation (or, if staying on 2019.3.1023, enable the non-default hardening setting); per CISA KEV, apply updates per vendor instructions. Because exploitation requires the encryption keys to be known, also patch the older CVE-2017-11317/CVE-2017-11357 key-disclosure flaws or rotate the Telerik upload encryption keys. Check internet-facing IIS/ASP.NET applications for exposed RadAsyncUpload handlers and indicators of compromise, given known ransomware and federal-agency breaches. | 9.8 | 100% | KEV ransomware PoC ×4 |
| largeTens of thousands of internet-exposed ASP.NET/IIS web applications using Telerik controls (order-of-magnitude estimate) |
Full article534 words · extracted from securityaffairs.com · click to collapse

Crooks exploit CVE-2019-18935 deserialization vulnerability to achieve remote code execution in Blue Mockingbird Monero-Mining campaign.
Researchers at security firm Red Canary uncovered a Monero cryptocurrency-mining campaign, tracked as Blue Mockingbird, that exploits the CVE-2019-18935 vulnerability in web applications built on the ASP.NET framework.
The deserialization vulnerability CVE-2019-18935 could be exploited by attackers to achieve remote code execution, it affects the Progress Telerik UI for ASP.NET AJAX and was also mentioned in a joint report released by the U.S. NSA and the Australian Signals Directorate (ASD) warning of attackers increasingly exploiting vulnerable web servers to deploy web shells.
This issue could be exploited only when the encryption keys are obtained via a separate attack, meaning that the attackers have to chain more exploits in their campaigns.
“Blue Mockingbird is the name we’ve given to a cluster of similar activity we’ve observed involving Monero cryptocurrency-mining payloads in dynamic-link library (DLL) form on Windows systems.” reads the report published by Red Canary experts. “They achieve initial access by exploiting public-facing web applications, specifically those that use Telerik UI for ASP.NET, followed by execution and persistence using multiple techniques “
Hackers targeted vulnerable versions of Telerik UI for ASP.NET to deploy the XMRig Monero-mining payload as a DLL on Windows systems. Experts also noticed that once compromised the system, attackers attempt lateral movements.
According to the experts, the Blue Mockingbird campaign is dated back at leak December 2019 and is still ongoing.
The researchers observed three distinct uses:
- Execution with rundll32.exe explicitly calling the DLL export fackaaxv;
- Execution using regsvr32.exe using the /s command-line option;
- Execution with the payload configured as a Windows Service DLL.
“Each payload comes compiled with a standard list of commonly used Monero-mining domains alongside a Monero wallet address,” continues the analysis. “So far, we’ve identified two wallet addresses used by Blue Mockingbird that are in active circulation. Due to the private nature of Monero, we cannot see the balance of these wallets to estimate their success.”
In order to achieve persistence, attackers first elevate their privileges with different techniques (using a JuicyPotato exploit to escalate privileges from an IIS Application Pool Identity virtual account to the NT Authority\SYSTEM account, stealing access credentials using the Mimikatz tool).
Then attackers use multiple persistence techniques, including the use of a COR_PROFILER COM hijack to execute a malicious DLL and restore items removed by defenders.
Blue Mockingbird threat actors move laterally by elevating privileges and using Remote Desktop Protocol (RDP) to access privileged systems and Windows Explorer to deploy the malicious payloads to remote systems.
Researchers speculate that attackers’ toolkit are still under active development.
“For mitigations, focus on patching web servers, web applications, and dependencies of the applications. Most of the techniques used by Blue Mockingbird will bypass whitelisting technologies, so the best route will be to inhibit initial access. Consider establishing a baseline of Windows Scheduled Tasks in your environment to know what is normal across your enterprise.” concludes the report.
Researchers also included Indicators of Compromise (IoCs) in the analysis they have published.
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Text extracted automatically; images, tables and formatting may be missing. Original: https://securityaffairs.com/103020/cyber-crime/blue-mockingbird-campaign.html