Fix ja3(s) length of strings used in MD5 computation + update MD5 functions

This commit is contained in:
William Robinet 2021-03-26 09:59:25 +01:00
parent 850ab0acb3
commit 04deb915a3

View file

@ -339,17 +339,22 @@ static int decode_HandshakeType_ClientHello(ssl,dir,seg,data)
snprintf(ja3_str, ja3_str_len, "%s,%s,%s,%s,%s",
ja3_ver_str, ja3_cs_str, ja3_ex_str, ja3_ec_str, ja3_ecp_str);
MD5_CTX md5;
UCHAR tmp[16];
EVP_MD_CTX *mdctx;
const EVP_MD *md;
unsigned char md_value[EVP_MAX_MD_SIZE];
unsigned int md_len, i;
MD5_Init(&md5);
MD5_Update(&md5, ja3_str, ja3_str_len);
MD5_Final(tmp,&md5);
md = EVP_get_digestbyname("MD5");
mdctx = EVP_MD_CTX_new();
EVP_DigestInit_ex(mdctx, md, NULL);
EVP_DigestUpdate(mdctx, ja3_str, strlen(ja3_str));
EVP_DigestFinal_ex(mdctx, md_value, &md_len);
EVP_MD_CTX_free(mdctx);
ja3_fp = calloc(33,1);
*ja3_fp = '\0';
for(int i=0; i<16; i++) {
snprintf(ja3_fp + strlen(ja3_fp), 3, "%02x", tmp[i]);
for(i=0; i<16; i++) {
snprintf(ja3_fp + strlen(ja3_fp), 3, "%02x", md_value[i]);
}
json_object_object_add(jobj, "ja3_str", json_object_new_string(ja3_str));
@ -475,17 +480,22 @@ static int decode_HandshakeType_ServerHello(ssl,dir,seg,data)
snprintf(ja3s_str, ja3s_str_len, "%s,%s,%s",
ja3s_ver_str, ja3s_c_str, ja3s_ex_str);
MD5_CTX md5;
UCHAR tmp[16];
EVP_MD_CTX *mdctx;
const EVP_MD *md;
unsigned char md_value[EVP_MAX_MD_SIZE];
unsigned int md_len, i;
MD5_Init(&md5);
MD5_Update(&md5, ja3s_str, ja3s_str_len);
MD5_Final(tmp,&md5);
md = EVP_get_digestbyname("MD5");
mdctx = EVP_MD_CTX_new();
EVP_DigestInit_ex(mdctx, md, NULL);
EVP_DigestUpdate(mdctx, ja3s_str, strlen(ja3s_str));
EVP_DigestFinal_ex(mdctx, md_value, &md_len);
EVP_MD_CTX_free(mdctx);
ja3s_fp = calloc(33,1);
*ja3s_fp = '\0';
for(int i=0; i<16; i++) {
snprintf(ja3s_fp + strlen(ja3s_fp), 3, "%02x", tmp[i]);
for(i=0; i<16; i++) {
snprintf(ja3s_fp + strlen(ja3s_fp), 3, "%02x", md_value[i]);
}
json_object_object_add(jobj, "ja3s_str", json_object_new_string(ja3s_str));