[DETECTION] Unknown packer (classes.dex) detection about apkid

[enovella]

Hi @ReBensk ,

I don't have a VT subscription, could you share these files in a ZIP file over here? Thanks

Edu

[ReBensk]

Sample1.zip
Sample2.zip
Samples Uploaded

[enovella]

Hi @ReBensk ,

I will try to create rules for this packer. Could you tell me unique patterns in these samples? And a made up name for it too?

[ReBensk]

rule Detect_Custom_Packer {
strings:
$aes_type = "AESTYPE"
$aes_string = "AES"
$encodeStr_func = "encodeStr"
$g_pass = "globalPass"
$e_pass = "encodePass"
$encodeToMD516_func = "encodeToMD516"
$encodeToMD5 = "encodeToMD5"

condition:
    any of them

}

[enovella]

rule Detect_Custom_Packer { strings: $aes_type = "AESTYPE" $aes_string = "AES" $encodeStr_func = "encodeStr" $g_pass = "globalPass" $e_pass = "encodePass" $encodeToMD516_func = "encodeToMD516" $encodeToMD5 = "encodeToMD5"

condition:
    any of them

}

This rule will produce many false positives due to the condition any of them with non-unique strings such as AES. What about all of them or 5 of them? Do you have opcodes, asset files, or other fingerprints instead of only-strings?

Lately, I don't get free time to look into this, feel free to pull-request any rule you want to and I will attempt reviewing it. Thanks for opening this ticket.

--Edu

[enovella]

@ReBensk Can you re-open the ticket and create this rule into a PR?

[ReBensk]

@ReBensk Can you re-open the ticket and create this rule into a PR?
Please refer the below ticket and created a new rule
#370