PDF malware analysis — malicious · 8b8615e53bf8f4fb

MALICIOUS

PDF

1.3 KB First seen: 2012-10-10

MD5: 7a8b349619da07c875f15b94bcc4f180 SHA-1: 1a258387133f8729b2e5ec9e6abf6a3e7121de8c SHA-256: 8b8615e53bf8f4fb6a155f31a1452dcbd2d07c03488f4cd401f323fd9c289e7d

148 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1059.007 JavaScript

The PDF document contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The unescape() function call suggests obfuscation, a common technique for hiding malicious payloads. The embedded JavaScript streams, javascript_obj0007_000.js and javascript_obj0007_001.js, are likely responsible for executing the malicious payload. The exact nature of the payload is not fully discernible due to obfuscation, but the presence of JavaScript within a PDF points to a common exploit delivery method.

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
```
 /S /JavaScript
 /JS (                for (#{rand3}=128;#{rand3}>=0;--#{rand3}) #{rand2} += unescape("#{nops}");
                while (#{rand5}.length<#{rand7}) #{rand5}+=#{rand5};
```
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0007_000.js`	pdf-javascript-stream	PDF /JS object 7 at offset 0x26D	433 bytes
SHA-256: `76f0624099d3a5c1a11c656311a99b79243927190593384d7f9bd4670f4885e9`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
Preview script First 1,000 lines of the extracted script for (#{rand3}=128;#{rand3}>=0;--#{rand3}) #{rand2} += unescape("#{nops}"); while (#{rand5}.length<#{rand7}) #{rand5}+=#{rand5}; while(#{rand9}.length+#{rand7} < 0x40000) #{rand9} = #{rand9}+#{rand9}+#{rand8}; for (#{rand11}=0;#{rand11}<1450;#{rand11}++) #{rand10}[#{rand11}] = #{rand9} + #{rand4}; while(#{rand12}.length < 0x4000) #{rand12}+=#{rand12};
`javascript_obj0007_001.js`	pdf-javascript-stream	PDF /JS object 7 at offset 0x26D	56 bytes
SHA-256: `be607296913e7bc7c9778fdb88cf2e978806e59147a78e771247b0ca7f7b7d36`
Preview script First 1,000 lines of the extracted script for (#{rand3}=128;#{rand3}>=0;--#{rand3}

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