Elise
Elise is a Windows backdoor, also referred to as Trensil and Page/BKDR_ESILE in the provided content, associated with the China-aligned espionage group Lotus Blossom. It was used in persistent spear-phishing campaigns, including activity exploiting Microsoft Office vulnerability CVE-2012-0158, to provide operators with persistent access to compromised systems. The malware is described as capable of executing commands and reading/writing files, and can launch a remote shell on the host to delete itself.
For persistence, Elise configures itself as a service; if service installation fails, it writes itself as svchost.exe under %APPDATA%\Microsoft\Network. A variant copies itself to a DLL and invokes it via rundll32.exe. The malware also creates a file under AppData\Local\Microsoft\Windows\Explorer to store harvested data locally before exfiltration.
For discovery and post-compromise activity, Elise executes commands including ipconfig /all, net start, and net user after initial communication with its remote server. For exfiltration and C2-related handling, the content states that Elise exfiltrates data using Base64-encoded cookie values and encrypts exfiltrated data with RC4. For defense evasion and anti-forensics, Elise performs timestomping on a CAB file it creates.
The content places Elise in the historical malware lineage of Lotus Blossom, noting that the group later transitioned from Elise to the Sagerunex backdoor family, with subsequent tooling including Hannotog and Chrysalis. Targeting context in the provided material links Lotus Blossom operations using Elise to long-running cyber-espionage activity against government, military, telecommunications, and other strategic sectors, particularly in the Asia-Pacific region.
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Vulnerabilities exploited
4 CVEs Mallory has correlated with this family across public research and vendor advisories. Each row links to the full Mallory page for that vulnerability.
...a persistent spear-phishing campaign that exploited a Microsoft Office flaw (CVE-2012-0158) to distribute a backdoor dubbed Elise (aka Trensil) that's designed to execute commands and read/write files.
CVE-2018-0802 and CVE-2017-11882: Critical memory corruption vulnerabilities in the legacy Microsoft Office Equation Editor (EQNEDT32.EXE) used extensively during “Spring Dragon” campaigns...
CVE-2016-1019: A critical Adobe Flash Player vulnerability exploited through watering hole attacks and spoofed Flash installer sites to deliver the Elise backdoor...
CVE-2018-0802 and CVE-2017-11882: Critical memory corruption vulnerabilities in the legacy Microsoft Office Equation Editor (EQNEDT32.EXE) used extensively during “Spring Dragon” campaigns to deliver Elise and Emissary Trojan payloads...
Groups observed using it
1 distinct threat actor attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.
...a persistent spear-phishing campaign that exploited a Microsoft Office flaw (CVE-2012-0158) to distribute a backdoor dubbed Elise (aka Trensil) that's designed to execute commands and read/write files.
Techniques & procedures
22 distinct techniques documented for this family, organized by ATT&CK tactic.
Execution
1 technique
Execution
Examples include "admin@338 actors used the following commands ... dir c:\ >> %temp%\download", "BabyShark has used dir to search for 'programfiles' and 'appdata'", and "FIN13 has used the Windows dir command to enumerate files and directories in a victim's network."
Persistence
3 techniques
Persistence
Across the content, malware repeatedly 'adds Registry Run keys', 'creates Registry entries', 'modifies the Windows Registry', or 'overwrites registry keys' to maintain persistence.
During the 2016 Ukraine Electric Power Attack, Sandworm Team used an arbitrary system service to load at system boot for persistence for Industroyer. They also replaced the ImagePath registry value of a Windows service with a new backdoor binary.
The content repeatedly describes malware and threat actors establishing persistence by adding values under HKCU/HKLM\Software\Microsoft\Windows\CurrentVersion\Run or RunOnce, and by placing executables, scripts, .lnk files, or .bat files in the Windows Startup folder.
Privilege Escalation
2 techniques
Privilege Escalation
During the 2016 Ukraine Electric Power Attack, Sandworm Team used an arbitrary system service to load at system boot for persistence for Industroyer. They also replaced the ImagePath registry value of a Windows service with a new backdoor binary.
The content repeatedly describes malware and threat actors establishing persistence by adding values under HKCU/HKLM\Software\Microsoft\Windows\CurrentVersion\Run or RunOnce, and by placing executables, scripts, .lnk files, or .bat files in the Windows Startup folder.
Stealth
6 techniques
Stealth
The content repeatedly describes payloads, strings, configuration files, scripts, URLs, and binaries being obfuscated or encoded using Base64, XOR, RC4, AES, RSA, hex encoding, custom algorithms, and other methods across many malware families and threat actors.
Examples throughout the content include 'encrypted payloads decrypted and executed in memory,' 'encrypts its configuration file,' 'AES-encrypted resource,' 'RC4 encrypted embedded scripts,' and 'payload includes an encrypted main component.'
During the 2016 Ukraine Electric Power Attack, DLLs and EXEs with filenames associated with common electric power sector protocols were used to masquerade files.
Akira has used legitimate names and locations for files to evade defenses.
The content repeatedly describes threat actors and malware deleting files, tools, scripts, logs, droppers, staged data, and artifacts from compromised systems to cover tracks, remove evidence, or self-delete.
APT28 has performed timestomping on victim files. APT29 has used timestomping to alter the Standard Information timestamps on their web shells to match other files in the same directory. APT32 has used scheduled task raw XML with a backdated timestamp... APT38 has modified data timestamps to mimic files that are in the same folder on a compromised host.
Defense Impairment
1 technique
Defense Impairment
Discovery
6 techniques
Discovery
"actors used the following command ... to obtain information about services: net start"; "APT1 used the commands net start and tasklist to get a listing of the services on the system"; "OilRig has used sc query on a victim to gather information about services"; "Indrik Spider has used the win32_service WMI class to retrieve a list of services"
The content repeatedly describes malware and threat actors using commands and APIs such as ipconfig /all, ifconfig, arp -a, route print, nbtstat, netsh, GetAdaptersInfo, and GetIpNetTable to gather IP addresses, MAC addresses, DNS, DHCP, gateways, routing tables, ARP cache, proxy settings, domains, and network adapter/interface details.
The content repeatedly describes malware and threat actors obtaining lists of running processes, using utilities such as tasklist, ps, WMI, Get-Process, CreateToolhelp32Snapshot, EnumProcesses, and similar APIs/commands to enumerate active processes on victim systems.
The content repeatedly describes malware and threat actors collecting host details such as OS version, hostname, architecture, CPU, memory, BIOS, domain, language, and other configuration data; e.g., "APT41 uses multiple built-in commands such as systeminfo and net config Workstation to enumerate victim system basic configuration information."
The content repeatedly describes malware and threat actors listing files and directories, enumerating drives, searching for files by extension/name/path, retrieving file metadata, and browsing file systems (for example: "APT28 has used Forfiles to locate PDF, Excel, and Word documents during collection" and "cmd can be used to find files and directories with native functionality such as dir commands").
“actors used the following commands… to enumerate user accounts: net user >> %temp%\download; net user /domain >> %temp%\download … APT1 used the commands net localgroup, net user, and net group to find accounts… APT32 enumerated administrative users using the commands net localgroup administrators … OilRig has run net user, net user /domain, net group "domain admins" /domain …”
Collection
2 techniques
Collection
Command and Control
3 techniques
Command and Control
The content repeatedly describes threat actors and malware using HTTP and HTTPS for command and control, such as: "Sandworm Team used BlackEnergy to communicate between compromised hosts and their command-and-control servers via HTTP post requests."
C2 traffic from ADVSTORESHELL is encrypted, then encoded with Base64 encoding... APT19 HTTP malware variant used Base64 to encode communications to the C2 server... APT33 has used base64 to encode command and control traffic.
"3PARA RAT command and control commands are encrypted within the HTTP C2 channel using the DES algorithm in CBC mode..."; "APT33 has used AES for encryption of command and control traffic."; "Carbanak encrypts the message body of HTTP traffic with RC2 (in CBC mode)."; "Duqu ... data stream can be encrypted with AES-CBC."; "PoisonIvy uses the Camellia cipher to encrypt communications."
Recent activity
32 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Custom backdoor used by Lotus Blossom, historically delivered via spear-phishing; supports remote command execution, file transfer, and reconnaissance with persistence via registry and other techniques and HTTP-based C2.
Backdoor family historically used by Lotus Blossom prior to switching to Sagerunex.
An earlier custom backdoor used by Lotus Blossom (noted in 2012–2015-era spearphishing campaigns) to establish persistent access for espionage.
A backdoor distributed via spear-phishing, designed to execute commands and read/write files on compromised systems.
The version that knows your environment.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.