Malicious PDF — malware analysis report

Static analysis result for SHA-256 e73d55a344b105e2…

MALICIOUS

PDF

17.3 KB
MD5: 8f9d0ee08190e99233191545474bc217 SHA-1: a6621e31b773f366ce02747b9fbae1f22a84a535 SHA-256: e73d55a344b105e2daf6701d27136306662e3e9660ac06f2504edc13ea994aa2
194 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

This PDF document is identified as malicious due to the presence of obfuscated JavaScript. The critical heuristic 'CVE_2007_5659' indicates the exploitation of a known Adobe Reader vulnerability. The 'PDF_JS_OBFUSCATED_DROPPER' heuristic further suggests that the embedded JavaScript acts as a multi-stage dropper, likely downloading and executing a second-stage payload. The presence of multiple extracted JavaScript files supports this multi-stage execution.

Heuristics 8

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • ClamAV: Pdf.Exploit.Agent-35901 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35901
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 4 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, 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. (matched inside decoded stream)
  • 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. (matched in decompressed stream)
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0009_000.js
4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d
pdf-javascript-stream PDF /JS object 9 at offset 0x42CD 469 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
696a2308682bcc7cff19d7c49766aaa682c5ee1b702287bb2611190a0c947f76
deobfuscated-js z-percent UTF-16BE base-21 decoded JavaScript at offset 0x1A84 5230 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
79ad4a386d20058cb16f49109801a9f3f2e8b50e5c4d4bc58dfd7d7d6bc3134e
deobfuscated-js PDF JavaScript deobfuscation pass 124324 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).