fesber | 229231a77d7ce10318e465ae1b9ce339ec04faa394eb98505293315c0136708c

Analysis

max time kernel
150s
max time network
142s
platform
windows10-2004_x64
resource
win10v2004-20260911-en
resource tags

arch:x64arch:x86image:win10v2004-20260911-enlocale:en-usos:windows10-2004-x64systemwindows
submitted
24/09/2026, 10:13

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General

Target
2026-09-23_3f5b292651ec6e674fdddeefe6ba1cc3_amadey_cobalt-strike_elex_hijackloader_icedid_njrat_vidar.exe
Size 4.7MB
Sample260924-l85pmaba75
SHA256 229231a77d7ce10318e465ae1b9ce339ec04faa394eb98505293315c0136708c
MD5 3f5b292651ec6e674fdddeefe6ba1cc3
SHA1 17d166393ec88088bd6772701b8665596b3f44c7
SHA512 78774e6055a6ee451f4ccdef1106fe2522a886f48f7575c3c662dcfeb893df2283a9d54300390b5526db1e9c0d69f1edecd8ca76561e836b5321015e95ca374f
SSDEEP 49152:jPd9ob7ko+4KuUOROgppYqcgjI45TMwwapIgTOPji0AjBgjI45TMwwapIgTFPjih:zDIkC69LapIJjozLapIIjo
TLSH
T15F366D26B2F14165D066C075CF829725EBF13C694BF086DB6245B3E82F33AD0763A726
MD5 SHA1 SHA512 SSDEEP TLSH

Score

10^/10

discovery fesber upx worm

Malware Config

Signatures

Family: Fesber
Fesber is a Windows worm written in Delphi.
worm fesber

Detects Fesber payload 2 IoCs

resource	yara_rule
behavioral1/memory/2080-0-0x0000000000400000-0x000000000041E000-memory.dmp	family_fesber
behavioral1/memory/2080-2-0x0000000000400000-0x000000000041E000-memory.dmp	family_fesber

Drops file in System32 directory 1 IoCs

description	ioc	Process
File created	C:\Windows\SysWOW64\fsb.stb	2026-09-23_3f5b292651ec6e674fdddeefe6ba1cc3_amadey_cobalt-strike_elex_hijackloader_icedid_njrat_vidar.exe

UPX packed file 2 IoCs

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

upx

resource	yara_rule
behavioral1/memory/2080-0-0x0000000000400000-0x000000000041E000-memory.dmp	upx
behavioral1/memory/2080-2-0x0000000000400000-0x000000000041E000-memory.dmp	upx

Program crash 1 IoCs

pid	pid_target	Process	procid_target
4972	2080	WerFault.exe	84

System Location Discovery: System Language Discovery 1 TTPs 1 IoCs

Attempt gather information about the system language of a victim in order to infer the geographical location of that host.

discovery

System Language Discovery

T1614.001

description	ioc	Process
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Control\NLS\Language	2026-09-23_3f5b292651ec6e674fdddeefe6ba1cc3_amadey_cobalt-strike_elex_hijackloader_icedid_njrat_vidar.exe

C:\Users\Admin\AppData\Local\Temp\2026-09-23_3f5b292651ec6e674fdddeefe6ba1cc3_amadey_cobalt-strike_elex_hijackloader_icedid_njrat_vidar.exe
"C:\Users\Admin\AppData\Local\Temp\2026-09-23_3f5b292651ec6e674fdddeefe6ba1cc3_amadey_cobalt-strike_elex_hijackloader_icedid_njrat_vidar.exe"
1⤵
- Drops file in System32 directory
- System Location Discovery: System Language Discovery
PID:2080
- C:\Windows\SysWOW64\WerFault.exe
  C:\Windows\SysWOW64\WerFault.exe -u -p 2080 -s 556
  2⤵
  - Program crash
  PID:4972

C:\Windows\SysWOW64\WerFault.exe
C:\Windows\SysWOW64\WerFault.exe -pss -s 408 -p 2080 -ip 2080
1⤵
PID:4520

Network

MITRE ATT&CK Enterprise v16

Reconnaissance

Resource Development

Initial Access

Execution

Persistence

Privilege Escalation

Defense Evasion

Credential Access

Discovery

System Location Discovery

T1614

System Language Discovery

T1614.001

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Replay Monitor

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Downloads

memory/2080-0-0x0000000000400000-0x000000000041E000-memory.dmp

Download

memory/2080-2-0x0000000000400000-0x000000000041E000-memory.dmp