Malicious PDF — malware analysis report

Static analysis result for SHA-256 e347fd4f04db2467…

MALICIOUS

PDF

31.4 KB
MD5: 1025a26582d5ad6a0980213adbcece8a SHA-1: 50ca9302037d065d0934f9465d0980cb7b996c2e SHA-256: e347fd4f04db2467c850938fb3cf215567b27a718381380d8aa17b486ecc9167
74 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Phishing: Spearphishing Attachment

The PDF contains obfuscated JavaScript, identified as a multi-stage dropper. The script performs anti-analysis checks and likely downloads a second-stage payload. The presence of 'deobfuscated.js' and 'javascript_obj0007_000.js' indicates the dropper's components. The attack pattern is consistent with a malicious document used for initial payload delivery.

Heuristics 6

  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, incremental_eval_build, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
  • JavaScript action low 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs.
  • 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
javascript_obj0007_000.js
f6c97065fa889619cb9a29fe74bbdc6f16ab91ffdbea8e9485e055c68a189b7a
pdf-javascript-stream PDF /JS object 7 at offset 0x149 443 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
deobfuscated.js
3a64e42bc6d8da24cd729e916f9ac878e4b351261c6c4b3c91d374b392a2980d
deobfuscated-js PDF JavaScript deobfuscation pass 596 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).