[Oisf-devel] File MD5 inconsistent checksums.
Nikolay Denev
ndenev at gmail.com
Thu Jul 12 06:27:35 UTC 2012
On Jul 12, 2012, at 9:25 AM, Nikolay Denev wrote:
> On Jul 12, 2012, at 9:03 AM, Nikolay Denev wrote:
>
>> Hi,
>>
>> I'm seeing some strange behaviour while testing the filemd5 and md5 checksumming in general.
>>
>> I have a server which serves a file over http and the server port on the switch is mirrored to a box running suricata.
>>
>> I have the md5 of the file as it is on the server : c2ddef96c8a1aeddf316ff3cba37f318
>> When I do a curl download and pipe it to md5 the checksum matches.
>>
>> :~ ndenev$ curl http://testserver.example.com/test.img | md5
>> % Total % Received % Xferd Average Speed Time Time Time Current
>> Dload Upload Total Spent Left Speed
>> 100 117k 100 117k 0 0 1744k 0 --:--:-- --:--:-- --:--:-- 1933k
>> c2ddef96c8a1aeddf316ff3cba37f318
>>
>> However the filemd5 rule I've created never matches, and files-json.log shows completely different checksums, which also are not consistent?
>> And the filesize too differs, and as I said the curl on the client machine gives the same md5 each time.
>>
>> { "timestamp": "07\/12\/2012-07:56:15.944637", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51135, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>> { "timestamp": "07\/12\/2012-07:56:25.033265", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51136, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "4b9fda98fbee8f4afea75b7b466b2e1a", "stored": false, "size": 3839 }
>> { "timestamp": "07\/12\/2012-07:56:30.232624", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51138, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>> { "timestamp": "07\/12\/2012-07:56:35.410789", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51140, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>> { "timestamp": "07\/12\/2012-07:56:39.225699", "ipver": 4, "srcip": "10.128.2.35", "dstip": "10.46.16.9", "protocol": 6, "sp": 80, "dp": 51142, "http_uri": "\/test.img", "http_host": "testserver.example.com", "http_referer": "<unknown>", "filename": "\/test.img", "magic": "ASCII text", "state": "CLOSED", "md5": "7890dc88c2f0f4d0706eef8bbfc33d75", "stored": false, "size": 4152 }
>>
>>
>> This is the latest entry in my stats.log :
>>
>> -------------------------------------------------------------------
>> Date: 7/12/2012 -- 08:00:24 (uptime: 0d, 00h 11m 20s)
>> -------------------------------------------------------------------
>> Counter | TM Name | Value
>> -------------------------------------------------------------------
>> tcp.sessions | Detect | 11097
>> tcp.ssn_memcap_drop | Detect | 0
>> tcp.pseudo | Detect | 6762
>> tcp.invalid_checksum | Detect | 22
>> tcp.no_flow | Detect | 0
>> tcp.reused_ssn | Detect | 0
>> tcp.memuse | Detect | 72351744
>> tcp.syn | Detect | 11520
>> tcp.synack | Detect | 10973
>> tcp.rst | Detect | 7998
>> tcp.segment_memcap_drop | Detect | 0
>> tcp.stream_depth_reached | Detect | 0
>> tcp.reassembly_memuse | Detect | 156557860
>> tcp.reassembly_gap | Detect | 3646
>> detect.alert | Detect | 24
>> decoder.pkts | RxPcapix01 | 7799419
>> decoder.bytes | RxPcapix01 | 6619532090
>> decoder.ipv4 | RxPcapix01 | 7732780
>> decoder.ipv6 | RxPcapix01 | 181
>> decoder.ethernet | RxPcapix01 | 7799419
>> decoder.raw | RxPcapix01 | 0
>> decoder.sll | RxPcapix01 | 0
>> decoder.tcp | RxPcapix01 | 4036503
>> decoder.udp | RxPcapix01 | 767312
>> decoder.sctp | RxPcapix01 | 0
>> decoder.icmpv4 | RxPcapix01 | 1957
>> decoder.icmpv6 | RxPcapix01 | 0
>> decoder.ppp | RxPcapix01 | 0
>> decoder.pppoe | RxPcapix01 | 0
>> decoder.gre | RxPcapix01 | 0
>> decoder.vlan | RxPcapix01 | 15588470
>> decoder.avg_pkt_size | RxPcapix01 | 849
>> decoder.max_pkt_size | RxPcapix01 | 1518
>> defrag.ipv4.fragments | RxPcapix01 | 0
>> defrag.ipv4.reassembled | RxPcapix01 | 0
>> defrag.ipv4.timeouts | RxPcapix01 | 0
>> defrag.ipv6.fragments | RxPcapix01 | 0
>> defrag.ipv6.reassembled | RxPcapix01 | 0
>> defrag.ipv6.timeouts | RxPcapix01 | 0
>> flow_mgr.closed_pruned | FlowManagerThread | 9036
>> flow_mgr.new_pruned | FlowManagerThread | 3033
>> flow_mgr.est_pruned | FlowManagerThread | 4478
>> flow.memuse | FlowManagerThread | 5401024
>> flow.spare | FlowManagerThread | 10034
>> flow.emerg_mode_entered | FlowManagerThread | 0
>> flow.emerg_mode_over | FlowManagerThread | 0
>
> I've now setup a rule to "filestore" the downloads so I can check them, and the stored files seem truncated.
>
> Also files-json.log continues to log "stored: false" while the files are actually saved.
>
>
The file on the server is about 120K, but the saved files are about 4K.
Which also reminds me that I've never actually saw a file much bigger than a few KBs in my files dir.
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