Malicious PDF — malware analysis report

Static analysis result for SHA-256 98b4079ea14decc1…

MALICIOUS

PDF

14.5 KB
MD5: c94b6676a814a31cab73c15a42f3eb4b SHA-1: 30ccfd80393718193d472c30289d2b3deabace30 SHA-256: 98b4079ea14decc1402dfe68c3b79cb12945e24d5f61f2bec6805979caa3b2dc
194 Risk Score

Malware Insights

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

The critical heuristic CVE_2007_5659 indicates exploitation of a known vulnerability in PDF documents. The PDF_JS_OBFUSCATED_DROPPER heuristic further suggests that the embedded JavaScript is designed to download and execute additional malicious content. The ClamAV detection confirms the malicious nature of the file. The deobfuscated JavaScript streams are too large and complex to analyze for specific actions, but the overall pattern points to a multi-stage 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 static 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 5 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, hex_dashed_payload, 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_obj0005_000.js
4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d
pdf-javascript-stream PDF /JS object 5 at offset 0x148 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
2ca9368f09e12e177ae07d89508fce4e87b2a6a5e84b2b3c3f6f5295902a87a5
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1862 11766 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
e6e686ee1e64b8db69b4815523d9ccaea4e8d4ac0b2e6058b67da4ac3df7eadb
deobfuscated-js PDF JavaScript deobfuscation pass 76801 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 9 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).