CHOPSTICK

MITRE ATT&CK: S0023 View on attack.mitre.org

Aliases: Backdoor.SofacyX, SPLM, Xagent, X-Agent, webhp, chopstick, fysbis, splm, CHOPSTICK

First seen
2012-01-01 00:00:00
Malware type
backdoor, rat
Family
Malware family
Operating systems
windows, linux
Related IoCs
2 (2 malicious)
Last IoC activity
2026-07-22 00:22:29
Profile updated
2026-07-07 12:43:10

Targeted industries: government-and-public-sector defense-and-aerospace

Targeted regions: country_code:us country_code:fr country_code:ge country_code:pl

Context

CHOPSTICK is a malware family of modular backdoors used by APT28. It has been used since at least 2012 and is usually dropped on victims as second-stage malware, though it has been used as first-stage malware in several cases. It has both Windows and Linux variants. It is tracked separately from the X-Agent for Android.

Recent IoC activity

2 malicious indicators in Maltiverse are attributed to CHOPSTICK (S0023). The 2 most recently updated:

TypeIndicatorUpdatedSources
hostname securesystemwin.com 2026-07-22 2
hostname advpdxapi.com 2025-09-04 2

Detection coverage

  • 1 YARA rules
  • 317 Sigma rules

Malware & tools used

  • Fallback Channels (attack-pattern)
  • Communication Through Removable Media (attack-pattern)
  • Internal Proxy (attack-pattern)
  • Command and Scripting Interpreter (attack-pattern)
  • Mail Protocols (attack-pattern)
  • Web Protocols (attack-pattern)
  • Modify Registry (attack-pattern)
  • Virtualization/Sandbox Evasion (attack-pattern)
  • Screen Capture (attack-pattern)
  • Ingress Tool Transfer (attack-pattern)
  • Security Software Discovery (attack-pattern)
  • File and Directory Discovery (attack-pattern)
  • Fileless Storage (attack-pattern)
  • Keylogging (attack-pattern)
  • Replication Through Removable Media (attack-pattern)
  • Domain Generation Algorithms (attack-pattern)
  • Symmetric Cryptography (attack-pattern)
  • Asymmetric Cryptography (attack-pattern)
  • Query Registry (attack-pattern)

Used by threat actors

Detection rules

  • MALPEDIA_Win_Xagent_Auto (yara-rule)

Related threat objects

Reports & references

  • Kaspersky — 83930 (report)
  • Broadcom/Symantec — Apt28 Espionage Military Government (report)
  • CrowdStrike — Bears Midst Intrusion Democratic National Committee (report)
  • Kaspersky — 72924 (report)
  • Mandiant — Wp Operation Quantum Entanglement (report)
  • Kaspersky — 97937 (report)
  • Broadcom/Symantec — Apt28 Espionage Military Government (report)
  • ti.qianxin.com — Cb78386A082F465F259B37Dae5Df4884 (report)
  • Kaspersky — 98440 (report)
  • malpedia.caad.fkie.fraunhofer.de — Elf.Xagent (report)
  • secureworks.com — Iron Twilight (report)
  • Palo Alto Unit 42 — A Look Into Fysbis Sofacys Linux Backdoor (report)
  • ESET — Eset Sednit Part 2 (report)
  • contagiodump.blogspot.de — Russian Apt Apt28 Collection Of Samples (report)
  • researchcenter.paloaltonetworks.com — A Look Into Fysbis Sofacys Linux Backdoor (report)
  • download.bitdefender.com — Bitdefender In Depth Analysis Of Apt28%E2%80%93The Political Cyber Espionage (report)
  • ESET — Sednit Reloaded Back Trenches (report)
  • Mandiant — Rpt Apt28 (report)
  • Mandiant — Apt28 Center Of Storm 2017 (report)
  • csecybsec.com — 20180713 Cse Apt28 X Agent Op Roman%20Holiday Report V6 1 (report)
  • ESET — Sednit Update Fancy Bear Spent Year (report)
  • malpedia.caad.fkie.fraunhofer.de — Win.Xagent (report)
  • thecssc.com — 4Octoberioc Apt28 Malware Advisory (report)
  • assets.documentcloud.org — Google Aquarium Clean (report)
  • MITRE ATT&CK — S0023 (report)

External references