WebShell Traffic Characterization

II. AntSword (AntSword v2.1)

① Much of the Ant Sword's code originates from Chinese kitchen knives, so its communication traffic is very similar to that of Chinese kitchen knives

②Built-in multipleencoderscap (a poem)codecThe encoding and encryption operations used for communication between the Ant Sword client and the Shell server can be used to bypass the WAF

③Support HTTP, HTTPS, SOCKS4, SOCKS5 four proxy protocols

④Custom encoders and decoders

1、AntSword default code

(1) Code analysis

1. Outputs the directory of the current script.

2. Judged the operating system

3. Current user information is obtained

4. Added to the beginning and end of the outputrandom string

(2) Packet analysis

(3) Summary of rules

['request_body']: =%40ini_set(%22display_errors%22%2C%20%220%22)%3B%40set_time_limit(0)%3B
['User-Agent']: antSword/v2.1 (weak signature)

2、AntSword base64 encoding

(1) Packet analysis

(2) Summary of rules

['request_body']: =QGluaV9zZXQoImRpc3BsYXlfZXJyb3JzIiwgIjAiKTtAc2V0X3RpbWVfbGltaXQoMCk7
['User-Agent']: antSword/v2.1 （weak characteristic）

3、AntSword ChR code

(1) Packet analysis

(2) Summary of rules

['request_body’]: cHr(64).ChR(105).ChR(110).ChR(105).ChR(95).ChR(115).ChR(101).ChR(116).ChR(40).ChR(34).ChR(100).ChR(105).ChR(115).ChR(112).ChR(108).ChR(97).ChR(121).ChR(95).ChR(101).ChR(114).ChR(114).ChR(111).ChR(114).ChR(115).ChR(34).ChR(44).ChR(32).ChR(34).ChR(48).ChR(34).ChR(41).ChR(59).ChR(64).ChR(115).ChR(101).ChR(116).ChR(95).ChR(116).ChR(105).ChR(109).ChR(101).ChR(95).ChR(108).ChR(105).ChR(109).ChR(105).ChR(116).ChR(40).ChR(48).ChR(41).ChR(59)
['User-Agent']: antSword/v2.1 (weak signature)

4、AntSword ChR16 code

(1) Packet analysis

(2) Summary of rules

['request_body’]: cHr(0x40).ChR(0x69).ChR(0x6e).ChR(0x69).ChR(0x5f).ChR(0x73).ChR(0x65).ChR(0x74).ChR(0x28).ChR(0x22).ChR(0x64).ChR(0x69).ChR(0x73).ChR(0x70).ChR(0x6c).ChR(0x61).ChR(0x79).ChR(0x5f).ChR(0x65).ChR(0x72).ChR(0x72).ChR(0x6f).ChR(0x72).ChR(0x73).ChR(0x22).ChR(0x2c).ChR(0x20).ChR(0x22).ChR(0x30).ChR(0x22).ChR(0x29).ChR(0x3b).ChR(0x40).ChR(0x73).ChR(0x65).ChR(0x74).ChR(0x5f).ChR(0x74).ChR(0x69).ChR(0x6d).ChR(0x65).ChR(0x5f).ChR(0x6c).ChR(0x69).ChR(0x6d).ChR(0x69).ChR(0x74).ChR(0x28).ChR(0x30).ChR(0x29).ChR(0x3b)
['User-Agent']: antSword/v2.1 （weak characteristic）

5、AntSword ROT13 code

(1) Packet analysis

(2) Summary of rules

['request_body']:%40vav_frg(%22qvfcynl_reebef%22%2C%20%220%22)%3B%40frg_gvzr_yvzvg(0)%3B
['User-Agent']: antSword/v2.1（weak characteristic）