Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c1a8730f1cef16f…

MALICIOUS

PDF

9.7 KB
MD5: 13020cbe38a0f0f726518d52fd5c90fa SHA-1: 30ede4aae6b2c6931799b63c5a0061b36dd5e9a8 SHA-256: 5c1a8730f1cef16fe878327343102ec9c762733bf67b5dcce48020501662941c
278 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that exploits CVE-2007-5659 via the syncAnnotScan primitive. This script is designed to decode a hex-encoded payload and then execute it. The decoded payload includes a URL, http://tdwvginbxps.com/nte/AVORP1TUTA8.html/eU230d9c2eH0700b428V0100f060006R00000000102T14b71c23203l000cK102613e8, which is likely used to download and execute a secondary stage. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 10

  • 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)
  • Adobe Reader APSB08-13 patch-range version gate (CVE-2007-5659) high CVE likely PDF_JS_ADOBE_APSB08_13_PATCH_GATE
    PDF JavaScript gates the exploit payload on (>= 8 && < 8.1.1) OR (< 7.1) — the Reader 7.0.x / 8.0–8.1.1 window patched by Adobe APSB08-13 for the CVE-2007-5659 Collab.collectEmailInfo buffer overflow. Only kits that target that exact bug check both of those patch points; benign scripts do not.
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://tdwvginbxps.com/nte/AVORP1TUTA8.html/eU230d9c2eH0700b428V0100f060006R00000000102T14b71c23203l000cK102613e8

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
b9a85ee399db318b3ad68d0755effe289a645a7404fad2094712c8a3fd042920
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 244 bytes
generic_stage_recovery_000.js
42e1f77e2ed23e12befc24f69b25b1726ec3445e5863b9fab5498a7bb2b67044
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x19B 234 bytes
annotation_subject_callee_hex_stage_000.js
a0661ffc1c137c8a64bcddbb37711f4878008c9bf84737c4486ab26d1007ee29
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5262 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
cf17f7d0c04a2c0b31cecf408fcc5fc07c0c2854351069f0508d5b731a9cd2f8
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2CA 12480 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
5a1db22b3dbacec70aaafa4440e7d62d268e3b8ac0f14e3471c1ebd4b2ff08f4
deobfuscated-js PDF JavaScript deobfuscation pass 74299 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).