BPFDoor is a Linux based passive long-term backdoor used by China-based threat actors. First seen in 2021, BPFDoor is named after its usage of Berkley Packet Filter (BPF) to execute single task instructions. BPFDoor supports multiple protocols for communicating with a C2 including TCP, UDP, and ICMP and can start local or reverse shells that bypass firewalls using iptables.[1][2]
13
Techniques57th pct
5
Tactics41st pct
0
Threat groupsNone recorded
0
CampaignsNone recorded
Enterprise ATT&CK only. Any Mobile or ICS rows on the same ATT&CK page are not carried.
After initial execution, BPFDoor forks itself and runs the fork with the --init flag, which allows it to execute secondary clean up operations. The parent process terminates leaving the forked process to be inherited by the legitimate process init.4
BPFDoor overwrites the argv[0] value used by the Linux /proc filesystem to determine the command line and command name to display for each process. BPFDoor selects a name from 10 hardcoded names that resemble Linux system daemons, such as; /sbin/udevd -d, dbus-daemon --system, avahi-daemon: chroot helper, /sbin/auditd -n, and /usr/lib/systemd/systemd-journald.5
After initial setup, BPFDoor's original execution process deletes the dropped binary and exits.8
Stealth30 detection rules
Standing S1161
Reach is how much of ATT&CK this malware touches. Coverage is how well defended each thing it does is, as a median per technique rather than a total — a total would just restate the reach. Each figure is ranked against all 825 ATT&CK software entries only where that population actually spreads. Where most of the population shares one value, a percentile would rank the tie instead of the entity, so the raw value is shown and no rank is claimed.
Reach
Techniques1357th pct
57th percentile · 57% of 825 ATT&CK software entries have this many Enterprise techniques or fewer.
Tactics541st pct
41st percentile · 59% of 825 ATT&CK software entries have more tactics spanned.
Threat groups061% tie · 22 values
61% of the population shares a single value across only 22 distinct values, so a percentile here would rank the tie, not the entity.
Campaigns085% tie · 8 values
85% of the population shares a single value across only 8 distinct values, so a percentile here would rank the tie, not the entity.
Coverage
Rules / technique3medBottom 3%
3rd percentile · 97% of 825 ATT&CK software entries have more detection rules per technique.
Tests / technique2medBottom 7%
7th percentile · 93% of 825 ATT&CK software entries have more atomic tests per technique.
Data comps / technique5med54% tie · 11 values
54% of the population shares a single value across only 11 distinct values, so a percentile here would rank the tie, not the entity.
Mitigations / technique1med57th pct
57th percentile · 57% of 825 ATT&CK software entries have this many mitigations per technique or fewer.
5 of 8 axes carry an honest rank on this page. Coverage medians are taken across this malware’s 13 Enterprise techniques.
Range
Technique Campaign use over its cumulative rule count.
Detects the Linux-specific execution chain of the plain-crypto-js malicious npm dependency by Axios NPM package, including payload download via curl and detached execution using nohup and python3. (...)
Detects the macOS-specific execution chain of the plain-crypto-js malicious npm dependency in Axios NPM Package, including AppleScript execution via osascript, payload download, permission modification, execution, and cleanup.
This analytic identifies Snort intrusion signatures that have been triggered by ten or more distinct internal IP addresses within a one-hour window. (...)
Teymur Kheirkhabarov (idea), Vasiliy Burov (rule), oscd.community, Tim Shelton
2020-10-11
2023-02-01
74403157-20f5-415d-89a7-c505779585cf
Splunk
The following analytic detects the execution of the curl utility where the command line includes percent-encoded characters and explicit file output options (such as -o or --output). (...)
This detection identifies when the ESXi firewall is disabled or set to permissive mode, which can expose the host to unauthorized access and network-based attacks. (...)
This detection identifies changes to the syslog configuration on an ESXi host using esxcli, which may indicate an attempt to disrupt log collection and evade detection.