Information regarding a group of Chinese APT cyber actors stealing high value information from commercial and governmental victims in the US and abroad was recently collected and analyzed by US federal authorities. This Chinese APT group is known within private sector reporting as APT10, Cloud Hopper, menuPass, Stone Panda, Red Apollo, CVNX and POTASSIUM. This group heavily targets managed service providers (MSP) who offer cloud computing services; commercial and governmental clients of MSPs; as well as defense contractors and governmental entities. APT10 uses various techniques for initial compromise including spear phishing and malware. After an initial compromise, this group seeks MSP administrative credentials to pivot between MSP cloud networks and customer systems in an effort to steal data and maintain persistence. This group has also used spear phishing to deliver malicious payloads and compromise victims.
REDLEAVES - The REDLEAVES implant is a remote access Trojan (RAT) which operates largely in memory with functionality suitable for system enumeration and lateral movement within victim networks. Industry reporting provides REDLEAVES may be used in spear phishing campaigns as an intrusion vector. REDLEAVES source code shares commonalities with TROCHILUS RAT. Variants of REDLEAVES include HIMAWARI and LAVENDER malware. REDLEAVES comprises an executable file (EXE), custom loader (DLL) and an encoded data file (DAT) containing shellcode and the REDLEAVES DLL.
Upon execution of the EXE file, the custom loader DLL is side-loaded and conducts a function call to load and decode an XOR encoded data file containing (a) stage-one shellcode, (b) stage two shellcode and (c) the REDLEAVES DLL. The stage-one shellcode launches "svchost.exe" to process hollow the stage-two shellcode; stage-two shellcode, in turn, allocates memory in "svchost.exe" to load REDLEAVES DLL. After the REDLEAVES DLL runs, the EXE file process terminates. REDLEAVES is able to utilize a named pipe to execute commands in remote shell or, alternatively, pass instructions through "cmd.exe" to execute commands directly in the command shell. Basic REDLEAVES functionality includes victim system enumeration, file search/deletion, screenshots, as well as data transmission. Prior to transmission, REDLEAVES compresses raw data with MiniLZO and encrypts said data with RC4 encryption. REDLEAVES is able to communicate with command and control (C2) servers on HTTP/HTTPS or custom TCP protocols across ports 53, 80, 443 and 995. Although REDLEAVES operates in memory to avoid detection, early versions may not conduct anti-forensics; evidence, therefore, of files copied to/from an infected host may still be present on disk. If a machine is believed to be infected, it is recommended to examine for "svchost.exe" processes which do not have "services.exe" as parent; "svchost.exe" memory pages mapped as read-write-execute (RWX); as well as reviewing forensic memory capture for anomalies commonly associated with malicious processes.
Installation commences when the victim user enables the Word document macro, resulting in the download of three Privacy Enhanced Mail (PEM) text files. These PEM files are decoded with "certutil.exe" to produce an EXE, DLL and DAT containing shellcode and the UPPERCUT DLL. Upon execution of the EXE file, the custom loader DLL is side-loaded and conducts a function call to load and decrypt the shellcode; the shellcode decodes and decompresses the UPPERCUT DLL. After the UPPERCUT DLL runs in memory, the PEM files are deleted with "esentutle.exe". UPPERCUT is known to use Blowfish encryption when communicating with C2 servers. UPPERCUT communicates with C2 servers through HTTP GET or POST requests. UPPERCUT initially collects victim computer information, such as hostname and OS version, and then aggregates and encrypts the data into a string embedded within the Uniform Resource Identifier (URI) of HTTP requests. Upon receiving an initial request, the C2 server will respond with an HTTP status response; if no C2 response is given, UPPERCUT may resend the HTTP request with a "GetLastError" code contained within the Cookie header.
Subsequent commands and modules between the C2 servers and UPPERCUT are Blowfish encrypted and then embedded within the body of HTTP requests or responses. Basic functionality includes the ability to execute commands, upload/download files, load executables and take screenshots.
CHCHES - CHCHES, also known as CHINESE CHESS, is a RAT which communicates with C2 servers using HTTP Cookie headers. Industry reporting provides CHCHES may be used in spear phishing campaigns as an initial intrusion vector designed to deploy second-stage payloads. The CHCHES EXE is known to disguise itself with a Word icon or shortcut, as well as use expired or revoked certificates. CHCHES initially collects victim computer hostname; process identifier (PID); current working directory (%TEMP%); screen resolution; as well as kernel32.dll or explorer.exe version.
QUASAR RAT - Please see APPENDIX A and APPENDIX B for technical indicators and indicators of compromise (IOCs) associated with this APT.
determined to be part of the compromise.
Patch all systems for critical vulnerabilities: A patch management process which regularly patches vulnerable software remains a critical component in raising the difficulty of intrusions for cyber operators. While a few adversaries use zero-day exploits to target victims, many adversaries still target known vulnerabilities for which patches have been released, capitalizing on slow patch processes and risk decisions by network owners not to patch certain vulnerabilities or systems. A few of these targeted vulnerabilities include the identified CVE's.
While watching for infections from the malware families detailed above, we also recommend ensuring you are patched against older vulnerabilities commonly exploited by cyber operators, such as CVE-2012-0158. After initial response activities, deploy and properly configure a mitigation tool kit such as Microsoft's Enhanced Mitigation Experience Toolkit (EMET). EMET employs several mitigations techniques to combat memory corruption techniques. It is recommended all hosts and servers on the network implement mitigation toolkits.
REDLEAVES configuration block structure overview (XOR encoded).
REDLEAVES C2 communication structure overview (TCP).
REDLEAVES sample, variant and/or artifact hash values.
UPPERCUT/ANEL C2 communication structure overview.
UPPERCUT/ANEL sample, variant and/or artifact hash values.
CHCHES C2 communication structure overview.
CHCHES sample, variant and/or artifact hash values.