Malicious PDF — malware analysis report

Static analysis result for SHA-256 98d02ae96b04793e…

MALICIOUS

PDF

8.4 KB
MD5: 2b036c5f6d6c058dcfbe0d49b689db9a SHA-1: aefda0d61fbb66095de34ddee0abf66ee58f1012 SHA-256: 98d02ae96b04793e6eaecb7436c74ee0d35cb02b0b49f7427b9360cbb53606d9
196 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link T1071.001 Web Protocols T1566.002 Spearphishing Attachment T1204.002 Malicious File

The PDF file contains obfuscated JavaScript, detected as a dropper, which leverages the CVE-2007-5659 vulnerability (Collab.collectEmailInfo). This vulnerability is used to decode and execute a multi-stage payload. The primary function appears to be downloading and executing a second-stage payload from a remote source, indicated by the dropper heuristic. The presence of multiple deobfuscated JavaScript files further supports the multi-stage nature of the attack.

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.Dropper.Agent-7285238-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7285238-0
  • 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, hex_dashed_payload, 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
9d5c7e01faed5b04e9ec11f1d98b73f0012c871beaf60e9f9d32ad6df00d46f7
pdf-javascript-stream PDF /JS object 5 at offset 0x148 550 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
c2628d5b06e895c39c0b5d0a903b58563aabc1c206e4716848f4431ccce048a8
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1CA2 1682 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
cd67aca584a02f49756cc6673b6131a824d2edb8a030a65f8359f74b69846712
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x359 5302 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
416cf47a401e2471dc44bbe9f259c6c50029c1fa22a95b5199c1ed46f65eb4fb
deobfuscated-js PDF JavaScript deobfuscation pass 20921 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).