sync_supers Generating High load Due to Brute SSH attack
My Alerting system has reported that one of the server is reporting high Load. The Server is in question has not been so stressed in recent past.So i was curios to look at it. While doing the Investigation i found that it was not a CPU load due to processes that are in the server. But it was a brute attack on the server. bssh2z (brute ssh) is for brute-forcing list of ips with various passwords is doing all the damage.
1. User krish (krish:x:500:500::/home/krish:/bin/bash) was running multiple instance of Perl Scripts, Which was attributing to High CPU Load. load average: 6.31, 5.83, 5.72
12215 krish 25 0 86224 3680 1140 R 99.9 0.0 924:27.46 perl
19900 krish 25 0 86224 3676 1140 R 99.9 0.0 3267:42 perl
26054 krish 25 0 86224 3720 1180 R 99.9 0.0 3589:34 perl
28916 krish 25 0 86224 3676 1140 R 99.9 0.0 2174:35 perl
29648 krish 25 0 86224 3680 1140 R 99.9 0.0 930:58.31 perl
23030 krish 25 0 86224 3680 1140 R 99.5 0.0 947:45.61 perl
2. After Checking Further Found, it was running sync_supers (File System Related process which flush the data to Disk) and http (Web Server).
krish 2408 0.0 0.0 86224 2848 ? S Sep19 0:00 [sync_supers]
krish 2409 0.0 0.0 63856 1060 ? S Sep19 0:00 sh -c ./bssh2z 300 22 10 CHANNEL >> .asd.log 2>&1 3>&1
krish 2410 0.0 0.0 2716 2604 ? S Sep19 0:01 /usr/sbin/http
3. All it was doing through the bssh2z (brute ssh) binary.
bssh2z: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), statically linked, stripped
krish pts/0 77.40.116.2 Wed Aug 31 16:52 - 16:52 (00:00)
krish pts/0 77.40.116.2 Wed Aug 31 16:34 - 16:34 (00:00)
krish pts/0 77.40.116.2 Wed Aug 31 16:13 - 16:13 (00:00)
Action Taken:
1. User “krish” deleted.
2. Process related to krish Killed.
3. Blocked SSH Access on Public IP .
1. User krish (krish:x:500:500::/home/krish:/bin/bash) was running multiple instance of Perl Scripts, Which was attributing to High CPU Load. load average: 6.31, 5.83, 5.72
12215 krish 25 0 86224 3680 1140 R 99.9 0.0 924:27.46 perl
19900 krish 25 0 86224 3676 1140 R 99.9 0.0 3267:42 perl
26054 krish 25 0 86224 3720 1180 R 99.9 0.0 3589:34 perl
28916 krish 25 0 86224 3676 1140 R 99.9 0.0 2174:35 perl
29648 krish 25 0 86224 3680 1140 R 99.9 0.0 930:58.31 perl
23030 krish 25 0 86224 3680 1140 R 99.5 0.0 947:45.61 perl
2. After Checking Further Found, it was running sync_supers (File System Related process which flush the data to Disk) and http (Web Server).
krish 2408 0.0 0.0 86224 2848 ? S Sep19 0:00 [sync_supers]
krish 2409 0.0 0.0 63856 1060 ? S Sep19 0:00 sh -c ./bssh2z 300 22 10 CHANNEL >> .asd.log 2>&1 3>&1
krish 2410 0.0 0.0 2716 2604 ? S Sep19 0:01 /usr/sbin/http
3. All it was doing through the bssh2z (brute ssh) binary.
bssh2z: ELF 32-bit LSB executable, Intel 80386, version 1 (GNU/Linux), statically linked, stripped
krish pts/0 77.40.116.2 Wed Aug 31 16:52 - 16:52 (00:00)
krish pts/0 77.40.116.2 Wed Aug 31 16:34 - 16:34 (00:00)
krish pts/0 77.40.116.2 Wed Aug 31 16:13 - 16:13 (00:00)
Action Taken:
1. User “krish” deleted.
2. Process related to krish Killed.
3. Blocked SSH Access on Public IP .
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